CN105632325A - Mercator map projection demonstration device and demonstration method - Google Patents

Abstract

The invention relates to a Mercator map projection demonstration device and a demonstration method. The demonstration device comprises a base, a bulb and a light-transmitting globe main body, wherein the bulb and the light-transmitting globe main body are arranged on the base. The bulb is arranged at the place of a globe center of the globe main body; the outer surface of the globe main body is marked with a deformation verification triangle, longitude and latitude lines and an equator; the globe main body is externally covered by a transparent map paper cover; the transparent map paper cover is cylinder in shape, and the center shaft thereof is overlapped with the earth axis of the globe main body; and the diameter of the transparent map paper cover is equal to the diameter of the equator of the globe main body, and the height of the transparent map paper cover is equal to the earth axis of the globe main body. The Mercator map projection process is demonstrated visually through a simple method, and meanwhile, the deformation verification triangle and a length verification line are utilized to demonstrate the deformation property of Mercator map projection vividly; and the demonstration device is convenient to get materials and easy to produce, can enable the abstract theory teaching to become visual and vivid, and greatly improves teaching effect of cartography.

Description

A Mercator map projection demonstration device and demonstration method

technical field

The invention belongs to the technical field of teaching demonstration tools for colleges and universities, and in particular relates to a Mercator map projection demonstration device and a demonstration method.

technical background

Maps, as a way of human image thinking and the second language of geography, have a long history and are still in the ascendant. Since the earth is an irregular sphere, in order to express the natural and human elements on the surface on a plane, it is necessary to use a map projection. However, there is no perfect map projection until now, because the ellipsoid of the earth is A non-developable surface must have area, length, and angle deformation during the map projection process. In front-line teaching, formula derivation or slide presentation is often used for map projection teaching, but the effect is not very satisfactory, because the theory here is more complicated and the process is more abstract, which is not easy for students to understand.

Contents of the invention

In order to enhance the intuition, vividness and interest of map projection teaching and solve the problem of poor teaching effect, the present invention provides a Mercator map projection demonstration device and method, using the device to demonstrate the entire process of Mercator projection, It enables students to intuitively observe the whole process of the conversion of ground features from spherical to flat, and understand the deformation properties and characteristics of Mercator projection.

The present invention also provides a demonstration method using the above-mentioned Mercator map projection demonstration device.

The technical solution adopted by the present invention to realize the above object is:

The Mercator map projection demonstration device includes a base, a light bulb installed on the base, and a translucent globe main body. The light bulb is set at the center of the globe main body, and the outer surface of the globe main body is marked with deformation verification triangles and lines of longitude, latitude, and equator. , a see-through paper cover is set outside the globe main body, the see-through paper cover is cylindrical, and its central axis coincides with the earth axis of the globe main body, the diameter of the see-through paper cover is equal to the equatorial diameter of the globe main body, and the height is equal to the earth axis of the globe main body .

The above-mentioned transparent paper cover is composed of a cylindrical sleeve and a transparent paper. The cylindrical sleeve is a cylindrical structure made of thin iron wire, and its cross section is circular. The diameters are equal, and the perspective paper is covered on the cylindrical sleeve to form a perspective paper cover.

The globe body includes a globe frame and a polyester film covering the outer surface of the globe frame, and the deformation verification triangle is pasted on the surface of the polyester film.

Utilize the map projection demonstration method of above-mentioned Mercator map projection demonstration device, realize by following steps:

(1) Turn on the power to make the light bulb shine, and the light emitted by the light bulb passes through the polyester film to make the warp, weft, and deformation verification triangle form a projection on the transparent paper cover;

(2) Use a pencil to draw the meridian and equator, the meridians on both sides of the meridian and the latitude on both sides of the equator one by one on the perspective paper cover, and then draw the projection line of the deformation verification triangle, and remove it along the direction of the generatrix of the perspective paper cover Perspective drawing, the figure drawn on the perspective drawing is the plane situation after Mercator projection;

(3) Measure the projection angle and equator length of the deformation verification triangle after projection on the perspective paper cover, compare the angle change and length change before and after projection, and calculate the area size of the deformation verification triangle before and after projection, so as to determine the Mercator projection Later angle deformation, length deformation and area deformation.

The Mercator map projection demonstration device and method of the present invention is to demonstrate the process of Mercator map projection by using a light bulb, a globe main body, and a light-transmitting transparent paper cover set outside the globe main body, that is, through a simple and convenient method that is intuitive and vivid. Simulate the Mercator projection process accurately, and at the same time use the deformation verification triangle and the length verification line to describe the deformation properties of the Mercator projection intuitively and vividly. In addition, the present invention is convenient for drawing materials, easy to design and manufacture, and can visualize abstract theoretical teaching. Vivid, which can attract students' attention, greatly improving the teaching effect of cartography.

Description of drawings

Fig. 1 is a schematic diagram of the internal structure of the Mercator map projection demonstration device in the embodiment.

Fig. 2 is a right side view of Fig. 1 .

FIG. 3 is a top view of FIG. 1 .

detailed description

The technical solutions of the present invention will now be further described in conjunction with the drawings and embodiments, but the present invention is not limited to the following implementation situations.

As shown in FIGS. 1-3 , the Mercator map projection demonstration device of this embodiment is composed of a base 1 , a perspective paper cover 2 , a light bulb 3 and a globe main body 4 .

Wherein, base 1 is common desk lamp base 1, and bulb 3 is installed on base 1, and globe main body 4 is also installed outside bulb 3, and bulb 3 is positioned at the center of inner cavity of globe main body 4, and globe main body 4 of the present embodiment It is composed of a simple globe frame that is lapped by thin iron wires to form a spherical network structure and a polyester film with good light transmission covering the globe frame. The bottom of the globe frame is fixed on the base 1, and the top is fixed with pins. Fastening, its specification is identical with the size of common globe, equatorial diameter is D, a right-angled deformation verification triangle 5 is pasted on the outer surface of polyester film, and each longitude line, latitude line and equator are marked, the two sides of deformation verification triangle 5 The right-angled sides are H and L respectively, and a see-through paper cover 2 is set outside the globe main body 4. The see-through paper cover 2 of this embodiment is composed of a cylindrical cover and a see-through paper, and the cylindrical cover is made of thin iron wire in a cylindrical structure. , its cross section is circular, its diameter is equal to the equatorial diameter of the globe main body 4, the height of the cylinder cover is equal to the earth axis of the globe main body 4, and the cylinder cover is covered with transparent paper to form a transparent paper cover 2, the transparent paper cover 2 The central axis coincides with the earth axis of the globe main body 4, and the inner surface of the perspective paper cover 2 is tangent to the two poles of the globe main body 4.

The method for performing map projection demonstration with the Mercator map projection demonstration device is realized by the following steps:

(1) After the power is turned on, the bulb 3 is made to emit light, and the light emitted by the bulb 3 causes the warp, weft, and deformation verification triangle 5 to form projections on the transparent paper cover 2 .

(2) Use a pencil to draw the prime meridian and the 0°-180° E meridian and 0°-180° W meridian on the left and right sides one by one on the perspective drawing cover 2, and draw the equator and the 0°-80° N latitude with a red pen , 0°～80°S parallel projection line, draw the projection line of the deformation verification triangle 5 with a blue pen, change the position of the deformation verification triangle 5, and draw another group corresponding to the deformation verification triangle 5 with a blue pen again For the projection line, remove the perspective drawing along the direction of the cylinder-covered generatrix, and the figure drawn on the perspective drawing is the plane situation after Mercator projection.

(3) Measure the angle and the area of the deformation verification triangle 5 at two positions on the polyester film, S=0.5HL, then measure the angle and area of the deformation verification triangle 5 after projection at the corresponding position on the perspective paper cover 2 s, compare the deformation before and after the projection to verify the angle and area change of the triangle 5, if the angle before and after the projection is equal, it means that the Mercator projection has no angular deformation, if the area before and after the projection is equal (S=s), it means that the Mercator projection has no area deformation, Otherwise, on the contrary; use a tape measure to measure the length of the equator on the polyester film and the length of the equator projected on the perspective paper cover 2, and compare the lengths of the equator before and after the projection. If the lengths are equal, it proves that the Mercator projection has no length distortion on the equator, so , determine the length, angle and area deformation after the Mercator map projection, and complete the Mercator map projection demonstration.

In the foregoing embodiment, the deformation verification triangle 5 can be adjusted in position according to the actual situation, and the angle of the triangle can also be adjusted appropriately. In the same way, the longitude and latitude marked on the outer surface of the globe main body 4 can also be adjusted appropriately. In the projection area where it is located, it is only necessary to make a comparison and description before and after projection, and it is not limited to the above-mentioned implementation situation.

Claims (4)

1. a Zhong Mo Kato map projection apparatus for demonstrating, it is characterized in that: comprise base (1) and the bulb (3) being arranged on base (1) and light transmission terrestrial globe main body (4), bulb (3) is arranged on the sphere center position of terrestrial globe main body (4), the outside surface of described terrestrial globe main body (4) is marked with distortion checking trilateral (5) and warp, parallel and equator, outer cover in terrestrial globe main body (4) is equipped with drawing cover (2), saturating drawing cover (2) is in cylinder shape, its central shaft overlaps with the earth's axis of terrestrial globe main body (4), the diameter of this saturating drawing cover (2) is equal with the equatorial diameter of terrestrial globe main body (4), height is equal with the earth's axis of terrestrial globe main body (4).

2. ink Kato map projection according to claim 1 apparatus for demonstrating, it is characterized in that: described drawing cover (2) is made up of cylindrical sleeve and saturating drawing, cylindrical sleeve makes cylindrical-shaped structure by thin iron wire, its cross section is rounded, the height of this cylindrical sleeve is equal with the earth's axis of terrestrial globe main body 4, diameter is equal with the equatorial diameter of terrestrial globe main body (4), is coated with drawing and forms drawing cover (2) in cylindrical sleeve.

3. ink Kato map projection according to claim 1 apparatus for demonstrating, it is characterized in that: the polyester film that described terrestrial globe main body (4) comprises terrestrial globe skeleton and covers on terrestrial globe skeleton outside surface, distortion checking trilateral (5) is pasted onto the surface of polyester film.

4. one kind utilizes map projection's demenstration method of the black Kato map projection apparatus for demonstrating described in claim 1, it is characterised in that realize by following step:

(1) making bulb (3) luminous after switching on power, the light that bulb (3) sends makes warp, parallel, distortion checking trilateral (5) form projection on saturating drawing cover (2) through polyester film;

(2) on saturating drawing cover (2), meridian and the parallel of equator and the warp in meridian both sides and both sides, equator is drawn with pencil one by one, draw the projection line of distortion checking trilateral (5) again, generatrix direction along saturating drawing cover (2) takes off drawing, and on saturating drawing, institute's drawing shape is the planar condition after Mercator projection;

(3) projection angle and the equator length of distortion checking trilateral (5) after the upper projection of drawing cover (2) is measured, relatively in angle change and the length variations of projection front and back, calculate the area size of distortion checking trilateral (5) before and after projection, so that it is determined that angular distortion after Mercator projection, length deformation and area distortion.