CN114419136B - A method and device for evaluating relative accuracy of topographic maps, and storage medium - Google Patents

Abstract

The present application discloses a method and device for evaluating the relative accuracy of a topographic map, a storage medium, and a computer device. The method includes: obtaining preset point set data corresponding to a target element, calculating a slope sequence and a curvature sequence corresponding to the preset point set, wherein the target element includes an arc bend element and/or a curved river element, the preset point set includes multiple inflection points, and the preset point set data includes multiple inflection point data; based on the slope sequence and the curvature sequence, determining a target arc point set corresponding to the target element; determining a target relative accuracy corresponding to the target arc point set, and determining the relative accuracy of a topographic map based on the target relative accuracy. The present application can automatically calculate the relative accuracy of a topographic map based on the preset point set data corresponding to the acquired target element, which can effectively reduce the cost of calculating the relative accuracy of a topographic map and improve the efficiency of evaluating the relative accuracy of a topographic map.

Description

A method and device for evaluating relative accuracy of topographic maps, and storage medium

Technical Field

The present application relates to the field of surveying and mapping geographic information technology, and in particular to a method and device for evaluating relative accuracy of a topographic map, a storage medium, and a computer device.

Background Art

The relative accuracy assessment of topographic maps plays an important role in ensuring the quality of basic geographic information. The design accuracy of topographic maps is mainly determined by the scale of the map, and whether the actual accuracy of topographic maps is consistent with the design accuracy requires the calculation of the relative accuracy of topographic maps.

The relative accuracy of existing topographic maps needs to be calculated through the spatial relative positions of feature features. This calculation method is inefficient and requires a lot of manpower and material resources, so it is costly. Therefore, how to reduce the cost of calculating the relative accuracy of topographic maps and improve the efficiency of evaluating the relative accuracy of topographic maps has become an urgent problem to be solved in this field.

Summary of the invention

In view of this, the present application provides a method and device for evaluating the relative accuracy of topographic maps, a storage medium, and a computer device, which can effectively reduce the cost of calculating the relative accuracy of topographic maps and improve the efficiency of evaluating the relative accuracy of topographic maps.

According to one aspect of the present application, a method for evaluating relative accuracy of a topographic map is provided, comprising:

Acquire preset point set data corresponding to the target element, and calculate the slope sequence and curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data;

Determine a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence;

The target relative accuracy corresponding to the target arc point set is determined, and based on the target relative accuracy, the relative accuracy of the topographic map is determined.

Optionally, the calculating of the slope sequence and the curvature sequence corresponding to the preset point set specifically includes:

Determine a slope sequence corresponding to the preset point set based on the inflection point data of every two adjacent inflection points in the preset point set data corresponding to the target element;

Based on the inflection point data of every three adjacent inflection points in the preset point set data corresponding to the target element, a target quadratic curve is fitted, and according to the target quadratic curve, a curvature sequence corresponding to the preset point set is determined.

Optionally, determining a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence specifically includes:

Extracting curvature trend items from the curvature sequence based on the empirical mode decomposition method, and segmenting the slope sequence based on positive and negative values corresponding to the curvature trend items;

The preset point set is screened according to the segmented slope sequence to obtain a target arc point set corresponding to the target element.

Optionally, the step of screening the preset point set according to the segmented slope sequence to obtain a target arc point set corresponding to the target element specifically includes:

According to the segmented slope sequence, determining whether the segmented slope sequence is monotonic;

When monotonicity is present, fitting the preset point set data based on a preset exponential function to obtain a first fitting result, calculating a corresponding first determination coefficient and a first fitting accuracy according to the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold, and the first fitting accuracy is greater than a first preset accuracy threshold, retaining the preset point set, and using the retained preset point set as a target arc point set, otherwise, discarding the preset point set;

When there is no monotonicity, the preset point set data is fitted based on a preset inverse proportional function to obtain a second fitting result, and the corresponding second determination coefficient and second fitting accuracy are calculated according to the second fitting result, and when the second determination coefficient is greater than the second preset coefficient threshold and the second fitting accuracy is greater than the second preset accuracy threshold, the preset point set is retained and the retained preset point set is used as the target arc point set; otherwise, the preset point set is divided into two sub-point sets according to monotonicity, and the preset exponential function is respectively fitted to obtain a third fitting result, and the corresponding third determination coefficient and third fitting accuracy are respectively calculated according to the third fitting result, and when the third determination coefficient is greater than the first preset coefficient threshold and the third fitting accuracy is greater than the first preset accuracy threshold, the corresponding sub-point set is retained and the retained sub-point set is used as the target arc point set, and when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, the corresponding sub-point set is discarded.

Optionally, after determining the target arc point set corresponding to the target element, the method further includes:

Based on the least squares method, a circle fitting is performed on the target arc point set to obtain a first circular curve corresponding to the target arc point set, and a first radius and a target center point corresponding to the first circular curve are determined;

According to a preset elimination condition, the inflection points in the target arc point set that meet the preset elimination condition are eliminated to obtain a first arc point set;

Reusing the least square method to perform circle fitting on the first arc point set to obtain a second circular curve, and determining a second radius corresponding to the second circular curve;

determining a radius change rate according to the first radius and the second radius;

When the radius change rate is less than or equal to a preset change rate threshold, taking the first arc point set as a designated arc point set, taking the second circular curve as a designated circular curve, and calculating the target relative accuracy based on the designated arc point set and the designated circular curve;

When the radius change rate is greater than the preset change rate threshold, the inflection points in the first arc point set that meet the preset elimination conditions are eliminated again according to the preset elimination conditions to obtain a second arc point set, and circle fitting is performed again to obtain a third circular curve, and the third radius corresponding to the third circular curve is determined, and the radius change rate is determined based on the second radius and the third radius until the radius change rate is less than or equal to the preset change rate threshold.

Optionally, removing the inflection points in the target arc point set that meet the preset removal condition according to the preset removal condition specifically includes:

According to the preset elimination conditions, three adjacent inflection points at the head end and three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the connection angle of the head end and the connection angle of the end, and when the connection angle is less than a first preset angle threshold or greater than a straight angle, the endpoint corresponding to the connection angle is eliminated, wherein the connection angle is the angle on one side of the target center; and/or,

According to the preset elimination condition, two adjacent inflection points at the beginning and the two adjacent inflection points at the end of the target arc point set are connected respectively to obtain the corresponding first line segment, a first perpendicular bisector of any of the first line segments is determined, and two nearest points of the two inflection points corresponding to the first line segment on the first circular curve are determined respectively, the two nearest points are connected to obtain a second line segment corresponding to the first line segment, a second perpendicular bisector of the second line segment is determined, a target perpendicular line angle is determined based on the first perpendicular bisector and the second perpendicular bisector, and when the target perpendicular line angle is greater than a second preset angle threshold, the endpoints of the two inflection points are eliminated; and/or,

According to the preset elimination conditions, the three adjacent inflection points at the beginning and the three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the target connecting line segment. When the sum of the target connecting line segments corresponding to any of the three adjacent inflection points is greater than or equal to the preset length threshold, the endpoints corresponding to the target arc point set in the three adjacent inflection points are eliminated.

Optionally, the calculating the target relative accuracy based on the specified arc point set and the specified circular curve specifically includes:

Based on the specified arc point set, determine the length of the line segment corresponding to each two adjacent inflection points in the specified arc point set to obtain the target total length;

Based on the specified circular curve, determining a target arc length corresponding to the specified circular curve;

The target relative accuracy is determined based on the target total length and the target arc length.

According to another aspect of the present application, a device for evaluating relative accuracy of a topographic map is provided, comprising:

A point set calculation module, used to obtain preset point set data corresponding to a target element, and calculate a slope sequence and a curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data;

A point set determination module, used to determine a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence;

The accuracy determination module is used to determine the target relative accuracy corresponding to the target arc point set, and determine the relative accuracy of the topographic map based on the target relative accuracy.

Optionally, the point set calculation module specifically includes:

A slope sequence determining unit, configured to determine a slope sequence corresponding to the preset point set based on the inflection point data of every two adjacent inflection points in the preset point set data corresponding to the target element;

The curvature sequence determination unit is used to fit a target quadratic curve based on the inflection point data of every three adjacent inflection points in the preset point set data corresponding to the target element, and determine the curvature sequence corresponding to the preset point set according to the target quadratic curve.

Optionally, the point set determination module specifically includes:

A segmentation unit, configured to extract a curvature trend term from the curvature sequence based on an empirical mode decomposition method, and segment the slope sequence based on positive and negative values corresponding to the curvature trend term;

The screening unit is used to screen the preset point set according to the segmented slope sequence to obtain a target arc point set corresponding to the target element.

Optionally, the screening unit is specifically used for:

According to the segmented slope sequence, determine whether the segmented slope sequence is monotonic; when it is monotonic, fit the preset point set data based on a preset exponential function to obtain a first fitting result, calculate a corresponding first determination coefficient and a first fitting accuracy based on the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold, and the first fitting accuracy is greater than a first preset accuracy threshold, retain the preset point set, and use the retained preset point set as the target arc point set, otherwise, discard the preset point set; when it is not monotonic, fit the preset point set data based on a preset inverse proportional function to obtain a second fitting result, calculate a corresponding second determination coefficient and a second fitting accuracy based on the second fitting result, and when the second determination coefficient is greater than a second preset coefficient threshold, and the second fitting accuracy is greater than the second preset accuracy threshold, retain the preset point set, and use the retained preset point set as the target arc point set; otherwise, divide the preset point set into two sub-point sets according to monotonicity, and fit them respectively according to the preset exponential function to obtain a third fitting result, calculate the corresponding third determination coefficient and the third fitting accuracy according to the third fitting result, and when the third determination coefficient is greater than the first preset coefficient threshold, and the third fitting accuracy is greater than the first preset accuracy threshold, retain the corresponding sub-point set, and use the retained sub-point set as the target arc point set; when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, discard the corresponding sub-point set.

Optionally, the device further comprises:

A circle fitting module, which is used for, after determining the target circular arc point set corresponding to the target element, performing circle fitting on the target circular arc point set based on the least square method to obtain a first circular curve corresponding to the target circular arc point set, and determining a first radius and a target circle center corresponding to the first circular curve;

A removal module, used for removing the inflection points in the target arc point set that meet the preset removal condition according to the preset removal condition, to obtain a first arc point set;

The circle fitting module is further used to re-use the least square method to perform circle fitting on the first arc point set to obtain a second circular curve, and determine a second radius corresponding to the second circular curve;

a change rate determination module, configured to determine a radius change rate according to the first radius and the second radius;

A judgment module is used to, when the radius change rate is less than or equal to a preset change rate threshold, use the first arc point set as a designated arc point set and the second circular curve as a designated circular curve, and calculate the target relative accuracy based on the designated arc point set and the designated circular curve; when the radius change rate is greater than the preset change rate threshold, again according to the preset elimination condition, eliminate the inflection points in the first arc point set that meet the preset elimination condition to obtain the second arc point set, and again perform circle fitting to obtain a third circular curve, determine a third radius corresponding to the third circular curve, and determine the radius change rate based on the second radius and the third radius until the radius change rate is less than or equal to the preset change rate threshold.

Optionally, the rejection module is specifically used to:

According to the preset elimination conditions, three adjacent inflection points at the beginning and three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the connection angle of the beginning and the connection angle of the end, and when the connection angle is less than the first preset angle threshold or greater than the straight angle, the endpoint corresponding to the connection angle is eliminated, wherein the connection angle is the angle on one side of the target center of the circle; and/or, according to the preset elimination conditions, two adjacent inflection points at the beginning and two adjacent inflection points at the end of the target arc point set are connected respectively to obtain the corresponding first line segment, determine the first perpendicular bisector of any of the first line segments, and respectively determine the two nearest points of the two inflection points corresponding to the first line segment on the first circular curve. , connect the two nearest points to obtain a second line segment corresponding to the first line segment, determine the second perpendicular bisector of the second line segment, determine the target perpendicular line angle based on the first perpendicular bisector and the second perpendicular bisector, and when the target perpendicular line angle is greater than a second preset angle threshold, remove the endpoints in the two inflection points; and/or, according to a preset removal condition, respectively connect the three adjacent inflection points at the beginning and the three adjacent inflection points at the end of the target arc point set to obtain a target connecting line segment, and when the sum of the target connecting line segments corresponding to any of the three adjacent inflection points is greater than or equal to a preset length threshold, remove the endpoints in the three adjacent inflection points corresponding to the target arc point set.

Optionally, the judging module is further configured to:

Based on the specified arc point set, determine the line segment length corresponding to each two adjacent inflection points in the specified arc point set to obtain the target total length; based on the specified circular curve, determine the target arc length corresponding to the specified circular curve; based on the target total length and the target arc length, determine the target relative accuracy.

According to another aspect of the present application, a storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the above-mentioned method for evaluating relative accuracy of a topographic map is implemented.

According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor implements the above-mentioned method for evaluating relative accuracy of topographic maps when executing the program.

By means of the above technical scheme, the present application provides a method and device for evaluating the relative accuracy of a topographic map, a storage medium, and a computer device. First, the preset point set data corresponding to the target element is obtained, and based on the preset point set data obtained, the slope sequence and curvature sequence corresponding to each preset point set are calculated. Then, the target arc point set corresponding to the target element can be further determined based on the slope sequence and the curvature sequence. Specifically, a part of the preset point set can be removed from the preset point set obtained according to the slope sequence and the curvature sequence, and the preset point set retained at last is the target arc point set. After determining the target arc point set, the target relative accuracy corresponding to the target arc point set can be further determined according to the target arc point set, and then the relative accuracy of the topographic map can be determined according to the target relative accuracy. The present application can automatically calculate the relative accuracy of the topographic map according to the preset point set data corresponding to the obtained target element, which can effectively reduce the cost of calculating the relative accuracy of the topographic map and improve the evaluation efficiency of the relative accuracy of the topographic map.

The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

FIG1 is a schematic diagram showing a flow chart of a method for evaluating relative accuracy of a topographic map provided in an embodiment of the present application;

FIG2 shows a schematic diagram of a method for refining discrete points at both ends of a target arc point set provided by an embodiment of the present application;

FIG3 shows a schematic diagram of another method for refining discrete points at both ends of a target arc point set provided by an embodiment of the present application;

FIG4 shows a schematic diagram of another method for refining discrete points at both ends of a target arc point set provided by an embodiment of the present application;

FIG5 shows a schematic structural diagram of a device for evaluating relative accuracy of a topographic map provided in an embodiment of the present application.

DETAILED DESCRIPTION

The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

In this embodiment, a method for evaluating relative accuracy of a topographic map is provided, as shown in FIG1 , the method comprising:

Step 101, obtaining preset point set data corresponding to a target element, and calculating a slope sequence and a curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data;

The relative accuracy evaluation method of a topographic map provided in the present application can be specifically applied to the client side or the server side. For a topographic map, relative accuracy evaluation is very important for ensuring the quality of basic geographic information on the topographic map. The road elements in the topographic map are basically composed of straight lines and curves, wherein the curves are mainly composed of circular curves. It can be considered that there must be arc features in the road elements, and the road elements corresponding to the arc features include arc curve elements, curved river elements, etc. The present application mainly calculates the relative accuracy of road elements with arc features in the topographic map. The present application can use arc curve elements and curved river elements as target elements. First, the preset topographic map toolbox can be called to convert the preset topographic map data into preset point set data corresponding to the target element. Here, the preset topographic map data can be data in shp format, the preset topographic map toolbox can be a Python geopandas library, and the Python geopandas library can be called to convert the data in shp format into preset point set data, wherein the preset point set can include multiple breakpoints, the preset point set data includes multiple breakpoint data, and the breakpoint data can be data with coordinates. Then, based on the acquired preset point set data, the slope sequence and curvature sequence corresponding to each preset point set are calculated. The topographic map may include multiple preset point sets, each preset point set corresponds to a set of preset point set data, so multiple preset point set data can be obtained, and then multiple slope sequences and curvature sequences can be calculated, each slope sequence and curvature sequence corresponds to a preset point set.

Step 102, determining a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence;

In this embodiment, after calculating the slope sequence and curvature sequence corresponding to each preset point set, the target arc point set corresponding to the target element can be further determined based on the slope sequence and curvature sequence. Specifically, a part of the preset point set can be removed from the acquired preset point set according to the slope sequence and curvature sequence, and the preset point set finally retained is the target arc point set.

Step 103, determining the target relative accuracy corresponding to the target arc point set, and determining the relative accuracy of the topographic map based on the target relative accuracy.

In this embodiment, after the target arc point set is determined, the target relative accuracy corresponding to the target arc point set can be further determined based on the target arc point set, and then the relative accuracy of the topographic map can be determined based on the target relative accuracy. For example, for a topographic map with a scale of 1:1 million, the design accuracy is 10m. It is possible to determine which target arc point sets meet the design accuracy of 10m based on the target relative accuracy, and further calculate the proportion of the target arc point sets that meet the design accuracy of 10m in the total arc point sets obtained, and then obtain the relative accuracy corresponding to the target elements in the topographic map.

By applying the technical solution of this embodiment, first, the preset point set data corresponding to the target element is obtained, and based on the preset point set data obtained, the slope sequence and curvature sequence corresponding to each preset point set are calculated. Then, the target arc point set corresponding to the target element can be further determined based on the slope sequence and curvature sequence. Specifically, a part of the preset point set can be removed from the preset point set obtained according to the slope sequence and the curvature sequence, and the preset point set finally retained is the target arc point set. After determining the target arc point set, the target relative accuracy corresponding to the target arc point set can be further determined according to the target arc point set, and then the relative accuracy of the topographic map can be determined according to the target relative accuracy. The present application can automatically calculate the relative accuracy of the topographic map according to the preset point set data corresponding to the obtained target element, which can effectively reduce the cost of calculating the relative accuracy of the topographic map and improve the evaluation efficiency of the relative accuracy of the topographic map.

Further, as a refinement and extension of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, another method for evaluating relative accuracy of a topographic map is provided, the method comprising:

Step 201, obtaining preset point set data corresponding to a target element, determining a slope sequence corresponding to the preset point set based on the inflection point data of every two adjacent inflection points in the preset point set data corresponding to the target element; fitting a target quadratic curve based on the inflection point data of every three adjacent inflection points in the preset point set data corresponding to the target element, and determining a curvature sequence corresponding to the preset point set based on the target quadratic curve;

In this embodiment, one or more sets of preset point set data corresponding to the target element are obtained, and the slope sequence and curvature sequence corresponding to each set of preset point set data are calculated respectively. The slope is calculated by calculating a slope according to each two adjacent inflection point data in the preset point set data, and finally putting these slopes together to obtain a slope sequence. For example, the preset point set data includes 5 inflection point data, namely _a1 ( _x1 , _y1 ), _a2 ( _x2 , _y2 ), _a3 ( _x3 , _y3 ), _a4 ( _x4 , _y4 ), and _a5 ( _x5 , _y5 ). For inflection point _a1 and inflection point _a2 , the corresponding slopes can be _h1 = ( _y2 - _y1 )/( _x2 - _x1 ), _h2 = ( _y3 - _y2 )/( _x3 - _x2 ), _h3 = ( _y4 - _y3 )/( _x4 - _x3 ) and _h4 = ( _y5 - _y4 )/( _x5 - _x4 ), and the final slope sequence can be [ _h1 , _h2 , _h3 , _h4 ]. The curvature is calculated by fitting a target quadratic curve based on the data of every three adjacent inflection points in the preset point set, and then calculating a corresponding curvature based on the target quadratic curve. Finally, these curvatures are put together to obtain a curvature sequence. For example, for three adjacent inflection points in the preset point set, if the parameter t satisfies the quadratic curve, the parameter equation is:

In the above formula (1), there are 6 unknown quantities (α ₁ , α ₂ , α ₃ ) and (β ₁ , β ₂ , β ₃ ), among which, for three adjacent inflection points, there are 6 known inflection point coordinates, namely (x ₁ , x ₂ , x ₃ ) and (y ₁ , y ₂ , y ₃ ). Therefore, three sets of equations can be listed according to the known inflection point coordinates, and then the 6 unknown quantities (α ₁ , α ₂ , α ₃ ) and (β ₁ , β ₂ , β ₃ ) can be solved. First, the value range is obtained through the two straight lines formed by the three points:

The conditions that t in the parametric equation should satisfy are:

Then we have:

The solution is that the curvature k is:

According to formula (6) and the (α ₁ , α ₂ , α ₃ ) and (β ₁ , β ₂ , β ₃ ) obtained by solving the data of every three adjacent inflection points, the corresponding curvature k can be obtained. Finally, the curvatures k are put together to obtain the curvature sequence.

Step 202: extracting curvature trend items from the curvature sequence based on the empirical mode decomposition method, and segmenting the slope sequence based on the positive and negative values corresponding to the curvature trend items; screening the preset point set according to the segmented slope sequence to obtain a target arc point set corresponding to the target element;

In this embodiment, after calculating the slope sequence and curvature sequence corresponding to each set of preset points, since the curvature of the present application is calculated through a series of discrete inflection points, abnormal curvature values may appear, causing the trend term of the curvature to be "swamped" by abnormal values. In order to obtain the curvature trend term and determine the basic characteristics (arcs) of the inflection points, the present application uses empirical mode decomposition (EMD) to decompose the nonlinear curvature sequence from high frequency to low frequency and convert it into multiple different, non-sinusoidal multi-scale signal components, namely, intrinsic mode functions (IMF). This algorithm can retain more available trend information. The core of EMD is to obtain the upper and lower envelopes based on cubic spline interpolation, and finally form an IMF process. Suppose there is a signal χ(t), which is represented by multi-scale components as:

Among them, r _n (t) represents the nth component, that is, the residual component. The first step for decomposition is to calculate the mean of the envelope:

Where _χa (t) is the mean of the envelope; _χu (t) and _χd (t) are the upper and lower envelopes, respectively.

IMF(t)＝χ(t) _-χa (t) (9)

IMF(t) needs to satisfy the condition of mean 0. If it satisfies the condition, it is an IMF component. Otherwise, the envelope is recalculated until the condition is satisfied. When only monotonic components remain, the signal is considered to be decomposed. At this time, there is:

r _n (t)=χ(t)-IMF _i (t) (10)

At this point, the extracted curvature trend item can be obtained. After the curvature trend item is obtained, the curvature trend item can have positive values or negative values. For a whole segment of positive values, the corresponding slope sequence can be divided into one segment. For a whole segment of negative values, the corresponding slope sequence can also be divided into one segment. After the slope sequence is segmented according to the positive and negative values of the curvature trend item, the corresponding multiple slope sequence segments can be obtained. After obtaining the segmented slope sequence, it can be determined whether the preset point set needs to be discarded according to each segment of the slope sequence, that is, the preset point set is screened, and the preset point set that does not meet the requirements is discarded from the preset point set, so as to obtain the target arc point set.

Step 203, performing circle fitting on the target arc point set based on the least square method to obtain a first circular curve corresponding to the target arc point set, and determining a first radius and a target center point corresponding to the first circular curve;

In this embodiment, after obtaining the target arc point set, the least squares method can be used to perform circle fitting on each group of target arc point sets. After fitting, the first circular curve corresponding to the target arc point set can be obtained. Then, the corresponding first radius is calculated based on the first circular curve, and the target center point corresponding to the first circular curve is determined.

Step 204, according to a preset elimination condition, eliminating the inflection points in the target arc point set that meet the preset elimination condition, to obtain a first arc point set;

In this embodiment, after obtaining the first circular curve, the inflection points in the target arc point set that meet the preset elimination conditions may be further eliminated according to the preset elimination conditions, and the first arc point set is obtained after elimination.

Step 205, performing circle fitting on the first arc point set again using the least square method to obtain a second circular curve, and determining a second radius corresponding to the second circular curve;

In this embodiment, since the first arc point set and the target arc point set contain different inflection points, after obtaining the first arc point set, the least squares method can be used again to perform circle fitting on the first arc point set to obtain a second circular curve corresponding to the first arc point set, and at the same time calculate the second radius corresponding to the second circular curve.

Step 206, determining a radius change rate according to the first radius and the second radius;

In this embodiment, after determining the first radius corresponding to the first circular curve and the second radius corresponding to the second circular curve, the corresponding radius change rate can be determined based on the first radius and the second radius.

Step 207, when the radius change rate is less than or equal to a preset change rate threshold, taking the first arc point set as a designated arc point set, taking the second circular curve as a designated circular curve, and calculating the target relative accuracy based on the designated arc point set and the designated circular curve;

In this embodiment, if the radius change rate corresponding to the first radius and the second radius is less than or equal to the preset change rate threshold, it means that the fitting degree of the circular curve is already good and there is no need to continue fitting. At this time, the first arc point set can be directly used as the designated arc point set, and at the same time, the second circular curve can be directly used as the designated circular curve. Then, based on the pointed arc point set and the designated circular curve, the corresponding target relative accuracy is calculated.

Here, the degree of circle fitting can also be determined by other conditions. For example, the number of iterations is preset, and when the circle fitting operation is repeated to reach the preset number threshold, the circle fitting is stopped, and the circular curve obtained by the last fitting is used as the designated circular curve. In addition, it is also possible to determine whether to stop the circle fitting operation by judging the change of the circle center corresponding to the circular curve of each circle fitting. For example, when the change rate of the circle center position is less than the preset position threshold, the circle fitting is stopped, and the circular curve obtained by the last fitting is used as the designated circular curve.

Optionally, the "calculating the target relative accuracy based on the specified arc point set and the specified circular curve" specifically includes: based on the specified arc point set, determining the line segment length corresponding to each two adjacent inflection points in the specified arc point set to obtain the target total length; based on the specified circular curve, determining the target arc length corresponding to the specified circular curve; determining the target relative accuracy based on the target total length and the target arc length.

In this embodiment, after the specified arc point set is determined, the length of the line segment corresponding to each two adjacent turning points in the specified arc point set can be determined based on the specified arc point set. For example, the specified arc point set can include 5 turning points, namely turning point 1 to turning point 5. Connect turning point 1 and turning point 2, turning point 2 and turning point 3, turning point 3 and turning point 4, turning point 4 and turning point 5 respectively, and 4 corresponding line segments can be obtained. Then, the lengths of these 4 line segments are added together to obtain the target total length. In addition, the target arc length corresponding to the specified circular curve can also be calculated, and finally the target relative accuracy is determined based on the calculated target total length and target arc length. Specifically, assuming that the target total length is _Ltotal and the target arc length is _Lar , the target relative accuracy can be ( _Lar - _Ltotal )/ _Ltotal .

Step 208, when the radius change rate is greater than the preset change rate threshold, the inflection points in the first arc point set that meet the preset elimination condition are eliminated again according to the preset elimination condition to obtain a second arc point set, and circle fitting is performed again to obtain a third circular curve, a third radius corresponding to the third circular curve is determined, and the radius change rate is determined according to the second radius and the third radius until the radius change rate is less than or equal to the preset change rate threshold;

In this embodiment, if the radius change rate corresponding to the first radius and the second radius is greater than the preset change rate threshold, it means that the fitting degree of the circular curve is not ideal and further fitting is required. At this time, the inflection points that meet the preset elimination conditions in the first arc point set can be eliminated according to the preset elimination conditions, thereby obtaining the second arc point set. Next, based on the second arc point set, the least squares method is also used to perform circular fitting to obtain the third circular curve, and the third radius corresponding to the third circular curve is calculated. After obtaining the third radius, the radius change rate of this fitting can be calculated based on the third radius and the second radius to determine the change size of the third radius. If the radius change rate of this time is less than or equal to the preset change rate threshold, the second arc point set can be used as the designated arc point set, and the third circular curve can be used as the designated circular curve to calculate the target relative accuracy; when the radius change rate of this time is greater than the preset change rate threshold, the above operation is continued until the radius change rate is less than or equal to the preset change rate.

Step 209: Determine the relative accuracy of the topographic map based on the target relative accuracy.

In this embodiment, after obtaining the target relative accuracy, the relative accuracy of the topographic map can be further determined according to the target relative accuracy. In addition, the relative accuracy of the topographic map can also be determined according to the feature distribution state and node density. Among them, the feature distribution state is to remap the elements that meet the design accuracy of the topographic map into the topographic map, observe the distribution state, establish the spatial mapping relationship between the element distribution and the basic geographic information map, and analyze the local characteristics of the element distribution; the node density is to calculate the ratio of the number of turning points of each element and the sum of the distances between its two adjacent points, that is, the number of turning points within the unit distance of each element, where the number of turning points refers to the number of turning points in the preset point concentration.

In an embodiment of the present application, optionally, the "screening the preset point set according to the segmented slope sequence to obtain the target arc point set corresponding to the target element" in step 202 specifically includes: judging whether the segmented slope sequence is monotonic according to the segmented slope sequence; when it is monotonic, fitting the preset point set data based on a preset exponential function to obtain a first fitting result, calculating the corresponding first determination coefficient and first fitting accuracy according to the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold and the first fitting accuracy is greater than a first preset accuracy threshold, retaining the preset point set and using the retained preset point set as the target arc point set, otherwise, discarding the preset point set; when it is not monotonic, fitting the preset point set data based on a preset inverse proportional function to obtain a second fitting result, and calculating the first fitting accuracy according to the second fitting result. The corresponding second determination coefficient and the second fitting accuracy are calculated, and when the second determination coefficient is greater than the second preset coefficient threshold and the second fitting accuracy is greater than the second preset accuracy threshold, the preset point set is retained, and the retained preset point set is used as the target arc point set; otherwise, the preset point set is divided into two sub-point sets according to monotonicity, and the preset exponential function is used to fit each of them to obtain a third fitting result, and the corresponding third determination coefficient and the third fitting accuracy are calculated according to the third fitting result, and when the third determination coefficient is greater than the first preset coefficient threshold and the third fitting accuracy is greater than the first preset accuracy threshold, the corresponding sub-point set is retained, and the retained sub-point set is used as the target arc point set; when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, the corresponding sub-point set is discarded.

In this embodiment, after the slope sequence is segmented using the curvature trend term, it is possible to further determine whether each segment of the slope sequence is monotonic based on the segmented slope sequence. For example, if the curvature trend term divides the slope sequence corresponding to the curvature sequence into four segments, it is possible to determine whether the four segments of the slope sequence are monotonic. When monotonicity exists, the preset exponential function can be used to fit the acquired preset point set, and a first fitting result corresponding to the preset point set can be obtained. Further, the corresponding first determination coefficient and first fitting accuracy can be calculated based on the first fitting result and the preset point set. Among them, the preset exponential function can be y _fit =a*exp(b*x)+c, the first determination coefficient can be expressed as R ² , the first fitting accuracy can be expressed as RMSE, and the first determination coefficient can be calculated by the following formula:

Among them, SS _res and SS _tot represent the residual sum of squares and the total sum of squares, respectively, as follows:

Among them, n is the number of inflection points in the preset point set, y is the y coordinate value corresponding to the inflection point in the preset point set, and y _fit is the y coordinate value obtained after fitting. Obviously, when the residual square sum is smaller, the better the fitting degree is, that is, the closer the first determination coefficient R ² is to 1, the better the fitting degree is. Similarly, the formula for the first fitting accuracy is as follows:

After calculating the first determination coefficient and the first fitting accuracy, the relationship between the first determination coefficient and the first preset coefficient threshold, and the relationship between the first fitting accuracy and the first preset accuracy threshold are further determined. When the first determination coefficient is greater than the first preset coefficient threshold, and at the same time the first fitting accuracy is greater than the first preset accuracy threshold, it means that the preset point set is an arc point set, and the preset point set can be retained and used as the target arc point set. Otherwise, it means that the preset point set is not an arc point set and can be discarded.

When monotonicity does not exist, it can be verified whether the preset point set belongs to a hyperbola, and thus the preset point set can be fitted using a preset inverse proportional function, and a second fitting result can be obtained after fitting. Further, the second determination coefficient and the second fitting accuracy can be calculated according to the second fitting result and the preset point set by formula (11) and formula (13). Among them, the preset inverse proportional function can be y _fit =1/(a*x+b). After calculating the second determination coefficient and the second fitting accuracy, the relationship between the second determination coefficient and the second preset coefficient threshold, and the relationship between the second fitting accuracy and the second preset accuracy threshold can be determined. If the second determination coefficient is greater than the second preset coefficient threshold, and at the same time the second fitting accuracy is greater than the second preset accuracy threshold, then it means that the preset point set is an arc point set, and the preset point set can be retained and used as the target arc point set. On the contrary, the preset point set can be further segmented into two monotonic sub-point sets, so that each sub-point set is monotonic, and then each sub-point set is fitted according to the preset exponential function. After fitting, the corresponding third fitting result can be obtained, and the third determination coefficient and the third fitting accuracy can be calculated respectively according to the third fitting result, wherein each sub-point set can correspond to a third fitting coefficient and a third fitting accuracy. Then, the third fitting coefficient is compared with the first preset coefficient threshold, and the third fitting accuracy is compared with the first preset accuracy threshold. When the third determination coefficient is greater than the first preset coefficient threshold, and the third fitting accuracy is greater than the first preset accuracy threshold, it means that the corresponding sub-point set is an arc point set, and the sub-point set can be retained and used as the target arc point set. On the contrary, it means that the corresponding sub-point set is not an arc point set and can be discarded.

In the embodiment of the present application, optionally, the step 204 of "eliminating the inflection points in the target arc point set that meet the preset elimination conditions according to the preset elimination conditions" specifically includes: according to the preset elimination conditions, respectively connecting the three adjacent inflection points at the head end and the three adjacent inflection points at the end of the target arc point set to obtain the connection angle of the head end and the connection angle of the end, and when the connection angle is less than a first preset angle threshold or greater than a straight angle, eliminating the endpoint corresponding to the connection angle, wherein the connection angle is the angle on one side of the target center of the circle; and/or, according to the preset elimination conditions, respectively connecting two adjacent inflection points at the head end and two adjacent inflection points at the end of the target arc point set to obtain the corresponding first line segment, determining the first perpendicular bisector of any of the first line segments, and Determine respectively the two nearest points of the two inflection points corresponding to the first line segment on the first circular curve, connect the two nearest points to obtain the second line segment corresponding to the first line segment, determine the second perpendicular bisector of the second line segment, determine the target perpendicular line angle based on the first perpendicular bisector and the second perpendicular bisector, and when the target perpendicular line angle is greater than a second preset angle threshold, remove the endpoints of the two inflection points; and/or, according to preset removal conditions, respectively connect the three adjacent inflection points at the beginning and the three adjacent inflection points at the end of the target arc point set to obtain the target connecting line segment, and when the sum of the target connecting line segments corresponding to any of the three adjacent inflection points is greater than or equal to the preset length threshold, remove the endpoints corresponding to the target arc point set in the three adjacent inflection points.

In this embodiment, after determining the target arc point set, the turning points in the target arc point set can be further eliminated according to the preset elimination conditions. For example, the three adjacent turning points at the head end in the target arc point set can be connected together, and the three adjacent turning points at the end can be connected together. The three connected turning points can form a connection angle, wherein the middle point of the three turning points is the vertex corresponding to the connection angle, and the connection angle refers to the angle on the side of the target circle center of the opening facing the fitting circle. Specifically, the three adjacent turning points at the head end correspond to the connection angle at the head end, and the three adjacent turning points at the end correspond to the connection angle at the end. When the angle of any connection angle is less than the first preset angle threshold, or the angle is greater than the flat angle, it means that the endpoints of the three adjacent turning points at the head end or the three adjacent turning points at the end have a greater impact on the circle fitting result and can be discarded. As shown in Figure 3, assuming that turning point A, turning point B and turning point C are the three adjacent turning points at the head end in the target arc point set, then angle ABC can be the head end connection angle, and the angle corresponding to the connection angle is equal to α ₁ +α _2. Since the angle of the connection angle is greater than the flat angle, turning point A can be discarded.

In addition, the two adjacent turning points at the head end of the target arc point set can be connected together, and the two adjacent turning points at the end can be connected together to obtain the corresponding first line segments, and then the first perpendicular bisector corresponding to each first line segment can be determined. Then, the second line segment corresponding to each first line segment can be further determined. Taking the first line segment corresponding to the two adjacent turning points at the head end as an example, the nearest points of the two turning points corresponding to the first line segment are found on the first circular curve, and the two nearest points are further connected to obtain the second line segment corresponding to the two nearest points, and the second perpendicular bisector corresponding to the second line segment is determined, wherein the second perpendicular bisector is a straight line passing through the center of the circle. Since the first perpendicular bisector and the second perpendicular bisector intersect, the target perpendicular angle can be obtained. The relationship between the target perpendicular angle and the second preset angle threshold is determined. If the target perpendicular angle is greater than the second preset angle threshold, it means that the endpoints of the two adjacent turning points have a greater impact on the circle fitting result and can be discarded. Here, the endpoint is the first point or the last point in the target arc point set. As shown in Figure 4, the inflection point X and the inflection point Y can be two adjacent inflection points at the beginning and the corresponding line segment XY connecting these two nodes is the first line segment, the straight line L1 is the first perpendicular bisector corresponding to the first line segment, the straight line L2 is the second perpendicular bisector, and the angle β is the target perpendicular line angle.

In addition, the three adjacent turning points at the head end of the target arc point set can be connected, and similarly, the three adjacent turning points at the end can be connected, so that four target connecting line segments can be obtained, wherein the three adjacent turning points at the head end correspond to two target connecting line segments, and the three adjacent turning points at the end correspond to two target connecting line segments. When the sum of the lengths of the two target connecting line segments corresponding to the three adjacent turning points at the head end is greater than or equal to the preset length threshold, the head end turning point in the target arc point set can be eliminated, and when the sum of the lengths of the two target connecting line segments corresponding to the three adjacent turning points at the end is greater than or equal to the preset length threshold, the end turning point in the target arc point set can also be eliminated. As shown in Figure 5, turning point M, turning point N and turning point P can be three turning points connected at the head end, and the corresponding target connecting line segments are line segment MN and line segment NP respectively. When the sum of the lengths of line segment MN and line segment NP is greater than the preset length threshold, if turning point M is the head end turning point in the target arc point set, then turning point M can be eliminated from the target arc point set.

In the real world, there are very likely to be long roads or very short winding roads, and the circular curve fitting may be successful. In this case, it is necessary to eliminate the overfitted point set. When the distance between any two adjacent inflection points in the target circular arc point set is greater than the preset distance threshold, the target circular arc point set is directly eliminated; when the radius of the circle after circle fitting is less than the preset radius threshold and the fitting accuracy of the fitted circular curve is greater than the preset accuracy threshold, the target circular arc point set is directly deleted; when the determination coefficient obtained based on the fitted circular curve and the target circular arc point set is less than the preset coefficient threshold, the target circular arc point set is directly deleted.

Further, as a specific implementation of the method of FIG. 1 , an embodiment of the present application provides a device for evaluating relative accuracy of a topographic map, as shown in FIG. 5 , the device includes:

A point set calculation module, used to obtain preset point set data corresponding to a target element, and calculate a slope sequence and a curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data;

A point set determination module, used to determine a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence;

The accuracy determination module is used to determine the target relative accuracy corresponding to the target arc point set, and determine the relative accuracy of the topographic map based on the target relative accuracy.

Optionally, the point set calculation module specifically includes:

A slope sequence determining unit, configured to determine a slope sequence corresponding to the preset point set based on the inflection point data of every two adjacent inflection points in the preset point set data corresponding to the target element;

The curvature sequence determination unit is used to fit a target quadratic curve based on the inflection point data of every three adjacent inflection points in the preset point set data corresponding to the target element, and determine the curvature sequence corresponding to the preset point set according to the target quadratic curve.

Optionally, the point set determination module specifically includes:

A segmentation unit, configured to extract a curvature trend term from the curvature sequence based on an empirical mode decomposition method, and segment the slope sequence based on positive and negative values corresponding to the curvature trend term;

The screening unit is used to screen the preset point set according to the segmented slope sequence to obtain a target arc point set corresponding to the target element.

Optionally, the screening unit is specifically used for:

According to the segmented slope sequence, determine whether the segmented slope sequence is monotonic; when it is monotonic, fit the preset point set data based on a preset exponential function to obtain a first fitting result, calculate a corresponding first determination coefficient and a first fitting accuracy based on the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold, and the first fitting accuracy is greater than a first preset accuracy threshold, retain the preset point set, and use the retained preset point set as the target arc point set, otherwise, discard the preset point set; when it is not monotonic, fit the preset point set data based on a preset inverse proportional function to obtain a second fitting result, calculate a corresponding second determination coefficient and a second fitting accuracy based on the second fitting result, and when the second determination coefficient is greater than a second preset coefficient threshold, and the second fitting accuracy is greater than the second preset accuracy threshold, retain the preset point set, and use the retained preset point set as the target arc point set; otherwise, divide the preset point set into two sub-point sets according to monotonicity, and fit them respectively according to the preset exponential function to obtain a third fitting result, calculate the corresponding third determination coefficient and the third fitting accuracy according to the third fitting result, and when the third determination coefficient is greater than the first preset coefficient threshold, and the third fitting accuracy is greater than the first preset accuracy threshold, retain the corresponding sub-point set, and use the retained sub-point set as the target arc point set; when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, discard the corresponding sub-point set.

Optionally, the device further comprises:

A circle fitting module, which is used for, after determining the target circular arc point set corresponding to the target element, performing circle fitting on the target circular arc point set based on the least square method to obtain a first circular curve corresponding to the target circular arc point set, and determining a first radius and a target circle center corresponding to the first circular curve;

A removal module, used for removing the inflection points in the target arc point set that meet the preset removal condition according to the preset removal condition, to obtain a first arc point set;

The circle fitting module is further used to re-use the least square method to perform circle fitting on the first arc point set to obtain a second circular curve, and determine a second radius corresponding to the second circular curve;

a change rate determination module, configured to determine a radius change rate according to the first radius and the second radius;

A judgment module is used to, when the radius change rate is less than or equal to a preset change rate threshold, use the first arc point set as a designated arc point set and the second circular curve as a designated circular curve, and calculate the target relative accuracy based on the designated arc point set and the designated circular curve; when the radius change rate is greater than the preset change rate threshold, again according to the preset elimination condition, eliminate the inflection points in the first arc point set that meet the preset elimination condition to obtain the second arc point set, and again perform circle fitting to obtain a third circular curve, determine a third radius corresponding to the third circular curve, and determine the radius change rate based on the second radius and the third radius until the radius change rate is less than or equal to the preset change rate threshold.

Optionally, the rejection module is specifically used to:

According to the preset elimination conditions, three adjacent inflection points at the beginning and three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the connection angle of the beginning and the connection angle of the end, and when the connection angle is less than the first preset angle threshold or greater than the straight angle, the endpoint corresponding to the connection angle is eliminated, wherein the connection angle is the angle on one side of the target center of the circle; and/or, according to the preset elimination conditions, two adjacent inflection points at the beginning and two adjacent inflection points at the end of the target arc point set are connected respectively to obtain the corresponding first line segment, determine the first perpendicular bisector of any of the first line segments, and respectively determine the two nearest points of the two inflection points corresponding to the first line segment on the first circular curve. , connect the two nearest points to obtain a second line segment corresponding to the first line segment, determine the second perpendicular bisector of the second line segment, determine the target perpendicular line angle based on the first perpendicular bisector and the second perpendicular bisector, and when the target perpendicular line angle is greater than a second preset angle threshold, remove the endpoints in the two inflection points; and/or, according to a preset removal condition, respectively connect the three adjacent inflection points at the beginning and the three adjacent inflection points at the end of the target arc point set to obtain a target connecting line segment, and when the sum of the target connecting line segments corresponding to any of the three adjacent inflection points is greater than or equal to a preset length threshold, remove the endpoints in the three adjacent inflection points corresponding to the target arc point set.

Optionally, the judging module is further configured to:

Based on the specified arc point set, determine the line segment length corresponding to each two adjacent inflection points in the specified arc point set to obtain the target total length; based on the specified circular curve, determine the target arc length corresponding to the specified circular curve; based on the target total length and the target arc length, determine the target relative accuracy.

It should be noted that for other corresponding descriptions of the functional units involved in the device for evaluating relative accuracy of a topographic map provided in the embodiment of the present application, reference can be made to the corresponding descriptions in the method of FIG. 1 , which will not be repeated here.

Based on the method shown in FIG. 1 , accordingly, an embodiment of the present application further provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for evaluating relative accuracy of a topographic map shown in FIG. 1 is implemented.

Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present application.

Based on the above method as shown in Figure 1 and the virtual device embodiment shown in Figure 5, in order to achieve the above purpose, the embodiment of the present application also provides a computer device, which can be specifically a personal computer, a server, a network device, etc. The computer device includes a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the above-mentioned relative accuracy assessment method of topographic maps as shown in Figure 1.

Optionally, the computer device may further include a user interface, a network interface, a camera, a radio frequency (RF) circuit, a sensor, an audio circuit, a WI-FI module, etc. The user interface may include a display, an input unit such as a keyboard, etc., and the optional user interface may also include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface, a wireless interface (such as a Bluetooth interface, a WI-FI interface), etc.

Those skilled in the art will appreciate that the computer device structure provided in this embodiment does not limit the computer device, and may include more or fewer components, or a combination of certain components, or different component arrangements.

The storage medium may also include an operating system and a network communication module. The operating system is a program that manages and saves the hardware and software resources of the computer device, and supports the operation of information processing programs and other software and/or programs. The network communication module is used to realize communication between the components inside the storage medium, and communication with other hardware and software in the physical device.

Through the description of the above implementation methods, those skilled in the art can clearly understand that the present application can be implemented by means of software plus the necessary general hardware platform, or by hardware. First, the preset point set data corresponding to the target element is obtained, and based on the preset point set data obtained, the slope sequence and curvature sequence corresponding to each preset point set are calculated. Then, the target arc point set corresponding to the target element can be further determined based on the slope sequence and the curvature sequence. Specifically, a part of the preset point set can be removed from the preset point set obtained according to the slope sequence and the curvature sequence, and the preset point set retained at last is the target arc point set. After determining the target arc point set, the target relative accuracy corresponding to the target arc point set can be further determined according to the target arc point set, and then the relative accuracy of the topographic map can be determined according to the target relative accuracy. The present application can automatically calculate the relative accuracy of the topographic map according to the preset point set data corresponding to the acquired target element, which can effectively reduce the cost of calculating the relative accuracy of the topographic map and improve the evaluation efficiency of the relative accuracy of the topographic map.

Those skilled in the art will appreciate that the accompanying drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the accompanying drawings are not necessarily necessary for implementing the present application. Those skilled in the art will appreciate that the modules in the devices in the implementation scenario can be distributed in the devices of the implementation scenario according to the description of the implementation scenario, or can be changed accordingly and located in one or more devices different from the present implementation scenario. The modules of the above-mentioned implementation scenario can be combined into one module, or can be further split into multiple submodules.

The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims (7)

1. A method for evaluating relative accuracy of a topographic map, comprising: Acquire preset point set data corresponding to the target element, and calculate the slope sequence and curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data; Determine a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence; Determine the target relative accuracy corresponding to the target arc point set, and determine the relative accuracy of the topographic map based on the target relative accuracy, wherein the target relative accuracy is determined based on the target total length and the target arc length, the target total length is determined based on the length of the line segment corresponding to each two adjacent inflection points in the specified arc point set, and the target arc length is determined based on the arc length corresponding to the specified circular curve; The determining, based on the slope sequence and the curvature sequence, a target arc point set corresponding to the target element specifically includes: Extracting curvature trend items from the curvature sequence based on the empirical mode decomposition method, and segmenting the slope sequence based on positive and negative values corresponding to the curvature trend items; According to the segmented slope sequence, determining whether the segmented slope sequence is monotonic; When monotonicity is present, fitting the preset point set data based on a preset exponential function to obtain a first fitting result, calculating a corresponding first determination coefficient and a first fitting accuracy according to the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold, and the first fitting accuracy is greater than a first preset accuracy threshold, retaining the preset point set, and using the retained preset point set as a target arc point set, otherwise, discarding the preset point set; When there is no monotonicity, the preset point set data is fitted based on a preset inverse proportional function to obtain a second fitting result, and the corresponding second determination coefficient and second fitting accuracy are calculated according to the second fitting result, and when the second determination coefficient is greater than the second preset coefficient threshold and the second fitting accuracy is greater than the second preset accuracy threshold, the preset point set is retained and the retained preset point set is used as the target arc point set; otherwise, the preset point set is divided into two sub-point sets according to monotonicity, and the preset exponential function is respectively fitted to obtain a third fitting result, and the corresponding third determination coefficient and third fitting accuracy are respectively calculated according to the third fitting result, and when the third determination coefficient is greater than the first preset coefficient threshold and the third fitting accuracy is greater than the first preset accuracy threshold, the corresponding sub-point set is retained and the retained sub-point set is used as the target arc point set, and when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, the corresponding sub-point set is discarded. 2. The method according to claim 1, characterized in that the step of calculating the slope sequence and the curvature sequence corresponding to the preset point set specifically comprises: Determine a slope sequence corresponding to the preset point set based on the inflection point data of every two adjacent inflection points in the preset point set data corresponding to the target element; Based on the inflection point data of every three adjacent inflection points in the preset point set data corresponding to the target element, a target quadratic curve is fitted, and according to the target quadratic curve, a curvature sequence corresponding to the preset point set is determined. 3. The method according to claim 1, characterized in that after determining the target arc point set corresponding to the target element, the method further comprises: Based on the least squares method, a circle fitting is performed on the target arc point set to obtain a first circular curve corresponding to the target arc point set, and a first radius and a target center point corresponding to the first circular curve are determined; According to a preset elimination condition, the inflection points in the target arc point set that meet the preset elimination condition are eliminated to obtain a first arc point set; Reusing the least square method to perform circle fitting on the first arc point set to obtain a second circular curve, and determining a second radius corresponding to the second circular curve; determining a radius change rate according to the first radius and the second radius; When the radius change rate is less than or equal to a preset change rate threshold, taking the first arc point set as a designated arc point set, taking the second circular curve as a designated circular curve, and calculating the target relative accuracy based on the designated arc point set and the designated circular curve; When the radius change rate is greater than the preset change rate threshold, the inflection points in the first arc point set that meet the preset elimination conditions are eliminated again according to the preset elimination conditions to obtain a second arc point set, and circle fitting is performed again to obtain a third circular curve, and the third radius corresponding to the third circular curve is determined, and the radius change rate is determined based on the second radius and the third radius until the radius change rate is less than or equal to the preset change rate threshold. 4. The method according to claim 3, characterized in that the step of eliminating the inflection points in the target arc point set that meet the preset elimination condition according to the preset elimination condition specifically comprises: According to the preset elimination conditions, three adjacent inflection points at the head end and three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the connection angle of the head end and the connection angle of the end, and when the connection angle is less than a first preset angle threshold or greater than a straight angle, the endpoint corresponding to the connection angle is eliminated, wherein the connection angle is the angle on one side of the target center; and/or, According to the preset elimination condition, two adjacent inflection points at the beginning and the two adjacent inflection points at the end of the target arc point set are connected respectively to obtain the corresponding first line segment, a first perpendicular bisector of any of the first line segments is determined, and two nearest points of the two inflection points corresponding to the first line segment on the first circular curve are determined respectively, the two nearest points are connected to obtain a second line segment corresponding to the first line segment, a second perpendicular bisector of the second line segment is determined, a target perpendicular line angle is determined based on the first perpendicular bisector and the second perpendicular bisector, and when the target perpendicular line angle is greater than a second preset angle threshold, the endpoints of the two inflection points are eliminated; and/or, According to the preset elimination conditions, the three adjacent inflection points at the beginning and the three adjacent inflection points at the end of the target arc point set are connected respectively to obtain the target connecting line segment. When the sum of the target connecting line segments corresponding to any of the three adjacent inflection points is greater than or equal to the preset length threshold, the endpoints corresponding to the target arc point set in the three adjacent inflection points are eliminated. 5. A device for evaluating relative accuracy of a topographic map, comprising: A point set calculation module, used to obtain preset point set data corresponding to a target element, and calculate a slope sequence and a curvature sequence corresponding to the preset point set, wherein the target element includes an arc curve element and/or a curved river element, the preset point set includes a plurality of inflection points, and the preset point set data includes a plurality of inflection point data; A point set determination module, used to determine a target arc point set corresponding to the target element based on the slope sequence and the curvature sequence; an accuracy determination module, for determining a target relative accuracy corresponding to the target arc point set, and determining a relative accuracy of a topographic map based on the target relative accuracy, wherein the target relative accuracy is determined based on a target total length and a target arc length, the target total length is determined based on a line segment length corresponding to each two adjacent inflection points in a specified arc point set, and the target arc length is determined based on an arc length corresponding to a specified circular curve; The point set determination module specifically includes: A segmentation unit, configured to extract a curvature trend term from the curvature sequence based on an empirical mode decomposition method, and segment the slope sequence based on positive and negative values corresponding to the curvature trend term; The screening unit is used to determine whether the segmented slope sequence is monotonic based on the segmented slope sequence; when it is monotonic, fit the preset point set data based on a preset exponential function to obtain a first fitting result, calculate the corresponding first determination coefficient and first fitting accuracy based on the first fitting result, and when the first determination coefficient is greater than a first preset coefficient threshold and the first fitting accuracy is greater than a first preset accuracy threshold, retain the preset point set and use the retained preset point set as the target arc point set, otherwise, discard the preset point set; when it is not monotonic, fit the preset point set data based on a preset inverse proportional function to obtain a second fitting result, calculate the corresponding second determination coefficient and second fitting accuracy based on the second fitting result, and when the second determination coefficient is greater than When the second preset coefficient threshold is reached and the second fitting accuracy is greater than the second preset accuracy threshold, the preset point set is retained and the retained preset point set is used as the target arc point set; otherwise, the preset point set is divided into two sub-point sets according to monotonicity, and the preset exponential function is used to fit each of them to obtain a third fitting result; the corresponding third determination coefficient and third fitting accuracy are calculated according to the third fitting result; when the third determination coefficient is greater than the first preset coefficient threshold and the third fitting accuracy is greater than the first preset accuracy threshold, the corresponding sub-point set is retained and the retained sub-point set is used as the target arc point set; when the third determination coefficient is less than the first preset coefficient threshold and/or the third fitting accuracy is less than the first preset accuracy threshold, the corresponding sub-point set is discarded. 6. A storage medium having a computer program stored thereon, wherein the computer program implements the method according to any one of claims 1 to 4 when executed by a processor. 7. A computer device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 4 when executing the computer program.