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Article
Peer-Review Record

Deformation-Adapted Spatial Domain Filtering Algorithm for UAV Mining Subsidence Monitoring

Sustainability 2024, 16(18), 8039; https://doi.org/10.3390/su16188039
by Jianfeng Zha 1,*, Penglong Miao 1, Hukai Ling 1, Minghui Yu 1, Bo Sun 1, Chongwu Zhong 2 and Guowei Hao 2
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Reviewer 4: Anonymous
Sustainability 2024, 16(18), 8039; https://doi.org/10.3390/su16188039
Submission received: 20 July 2024 / Revised: 11 September 2024 / Accepted: 11 September 2024 / Published: 14 September 2024
(This article belongs to the Section Pollution Prevention, Mitigation and Sustainability)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper proposes a spatial domain filtering algorithm for unmanned aerial photogrammetric images combined with mining deformation based on the characteristics of surface subsidence distribution in coal extraction. The reading is very smooth, and the document is written in good English. However, I would recommend using impersonal verb forms.

 

There are several acronyms in the document that, although they may be well-known in the scientific community, I believe should be spelled out to facilitate understanding for other scholars who are not strictly experts in this field. In particular: UAV, GNSS, LiDAR, SAR, ATIN, and CFS.

Line 131: I suggest using SI units, converting 0.0012 km^2 to m^2. Later, in fact, the meter will be used as the unit of measure.

A summary table of the percentage values could be introduced to better show the results obtained and the improvements introduced with this new method.

It is not clear how the differences between the point clouds are evaluated to observe the changes that the terrain undergoes (I am referring to what is shown in Figures 11 and 12). I assume it could be a deviation analysis based on the point-to-point distance between the two point clouds. If so, I believe it is appropriate for the authors to introduce a brief paragraph explaining what was actually done. In particular, they should introduce what deviation analysis is, provide some bibliographic references, and explain the method used. I would also like to suggest some of the most recent methods for evaluating differences between point clouds, which could be of interest to the authors and readers, also to improve the paper and/or for further developments on the topic addressed:

- https://doi.org/10.1007/978-3-031-58094-9_50

- https://doi.org/10.1016/j.robot.2022.104136

- https://doi.org/10.3390/ASEC2023-15245

Author Response

Comment 1: The paper proposes a spatial domain filtering algorithm for unmanned aerial photogrammetric images combined with mining deformation based on the characteristics of surface subsidence distribution in coal extraction. The reading is very smooth, and the document is written in good English. However, I would recommend using impersonal verb forms.

Response: Thanks for your advice. The form of this article has all been modified to the impersonal verb form, such as lines 248, 250, 252 and 287, etc.

 

Comment 2: There are several acronyms in the document that, although they may be well-known in the scientific community, I believe should be spelled out to facilitate understanding for other scholars who are not strictly experts in this field. In particular: UAV, GNSS, LiDAR, SAR, ATIN, and CFS.

Response: Thanks for pointing out the question. We have spelled out the full names of these shortened words.

 

Comment 3: Line 131: I suggest using SI units, converting 0.0012 km^2 to m^2. Later, in fact, the meter will be used as the unit of measure.

Response: Thanks for pointing out the mistake. We have changed the units to m^2.

 

Comment 4: A summary table of the percentage values could be introduced to better show the results obtained and the improvements introduced with this new method.

Response: Thanks for your advice. We have plotted a percentage summary table, as shown in Table 4.

 

Comment 5: It is not clear how the differences between the point clouds are evaluated to observe the changes that the terrain undergoes (I am referring to what is shown in Figures 11 and 12). I assume it could be a deviation analysis based on the point-to-point distance between the two point clouds. If so, I believe it is appropriate for the authors to introduce a brief paragraph explaining what was actually done. In particular, they should introduce what deviation analysis is, provide some bibliographic references, and explain the method used. I would also like to suggest some of the most recent methods for evaluating differences between point clouds, which could be of interest to the authors and readers, also to improve the paper and/or for further developments on the topic addressed.

Response: Thank you for your question. We have explained this issue in the text, specifically in lines 419 - 432. In the meantime, we have carefully considered your proposal for a point cloud discrepancy assessment methodology and have conducted an in-depth study. We note that point cloud quality evaluation is an evolving field that involves multiple challenges and key technologies. We also recognize that in order to improve the quality and depth of our paper, the discussion section needs to be further expanded, especially on the application and effectiveness of point cloud discrepancy assessment methods. In response to your suggestions, we plan to explore and integrate some of the latest point cloud disparity assessment techniques in our future work.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper outlines a new method for detecting surface displacement by differentiating Digital Elevation Models (DEMs) generated through UAV photogrammetry. The study is interesting but needs improvements to be suitable for publication.

The title can be improved, highlighting the use of Digital Elevation Models obtained through UAV photogrammetry for surface displacement mapping.

Overall, the English is acceptable, but there are parts of the text where clarity is compromised, such as in lines 145-146, 297-299, 307, 328-331, 355-357, and 379-381.

Line 122: Explain the term “working face”.

Line 126: “Study area overview” must be separated from the item “Materials”. Authors are encouraged to provide detailed information about the study area and include illustrations. Readers have no clear understanding of what is happening in the study area.

Line 159: Table 1 should include data regarding the UAV camera, UAV photo accuracy, etc. The authors should explain how the overflights were planned and how UAV photos were processed to obtain the Digital Elevation Models.

Figure 1 lacks a scale bar. Authors are encouraged to provide information about the leveling points in this figure, specifying which ones were used and which were not used for validation purposes.

I suggest incorporating subitem 2.3 into item 3.

In subitem 3.1, the authors should define the terms DSM, DEM, and CFS.

Figure 2 the authors are encouraged to provide clear information about the axis legends.

In subitem 3.2, the authors should prepare a figure summarizing the processing chain for clarity.

Lines 241-242: The authors should better explain this step.

Line 243: Do the authors mean the “regenerated” DEM or the original DEM after CFS filtering?

Figures 8 and 9: The legends of the graphs must be better presented. I suggest “along road” and “across road” instead of “the path of strike direction” and “the path of dip direction”.

Figure 10: Please plot all curves in the same graph for comparison.

Line 351: Use “Case study” instead of “Engineering application results.”

Line 361: Explain the term “phase.”

Figure 11: Clarify what the positive and negative values mean.

Line 363: Replace “deformation” with “displacement” throughout the paper. The terms have distinct meanings.

Line 373: Use “Accuracy assessment” instead of “Analysis of Sinking Extraction Results.”

Figure 13 Legend: Accuracy assessment for different mining phases: a) phase IV direction E-W; b) phase IV direction N-S; c) phase V direction E-W; d) phase V direction N-S; e) phase VI direction E-W; and f) phase VI direction N-S. Please delete the legends below each graph.

Items 5 and 6: I encourage the authors to combine these into one item only. I suggest highlighting the pros and cons of the proposed algorithm. For example, what is stated in lines 408 and 432 is very interesting for those who plan to apply the method.

Comments on the Quality of English Language

Overall, the English is acceptable, but there are parts of the text where clarity is compromised, such as in lines 145-146, 297-299, 307, 328-331, 355-357, and 379-381.

Author Response

Comment 1: The title can be improved, highlighting the use of Digital Elevation Models obtained through UAV photogrammetry for surface displacement mapping.

Response: Thank you for your advice. As the method in this paper is based on the surface change values of the surface changes due to coal mining to divide the filter grid, where the DEM is also to reflect the surface changes. Therefore, we are very sorry that we cannot emphasize the DEM as you suggested.

 

Comment 2: Overall, the English is acceptable, but there are parts of the text where clarity is compromised, such as in lines 145-146, 297-299, 307, 328-331, 355-357, and 379-381.

Response: Thanks for pointing out the question. We have described these sentences more clearly, such as: lines 361, 385-388, 419-432, etc.

 

Comment 3: Overall, the English is acceptable, but there are parts of the text where clarity is compromised, such as in lines 145-146, 297-299, 307, 328-331, 355-357, and 379-381.

Response: Thanks for pointing out the question. We have already explained the meaning of this word in line 147.

 

Comment 4: Line 126: “Study area overview” must be separated from the item “Materials”. Authors are encouraged to provide detailed information about the study area and include illustrations. Readers have no clear understanding of what is happening in the study area.

Response: Thanks for your suggestion. We have separated the “Overview of the Study Area” from the “Materials” section and given it a separate section in Chapter 2, with a more detailed description of the study area.

 

Comment 5: Line 159: Table 1 should include data regarding the UAV camera, UAV photo accuracy, etc. The authors should explain how the overflights were planned and how UAV photos were processed to obtain the Digital Elevation Models.

Response: Thank you for asking this question. But the UAV camera, UAV photo accuracy, etc. are already shown in Table I, such as: the second row, second column and the second row, third column in Table I. And the flight parameters are described in rows 191-192. For how to generate the DEM, this paper provides additional explanation in section 4.3.

 

Comment 6: Figure 1 lacks a scale bar. Authors are encouraged to provide information about the leveling points in this figure, specifying which ones were used and which were not used for validation purposes.

Response: Thanks for pointing out the question. We have modified Figure 1. In response to the question of which observation points were used, we have provided additional information in lines 457-461.

 

Comment 7: I suggest incorporating subitem 2.3 into item 3.

Response: Thanks for your suggestion. We have already incorporated, as shown in Subitem 4.1.

 

Comment 8: In subitem 3.1, the authors should define the terms DSM, DEM, and CFS.

Response: Thanks for pointing out the question. We have already defined the meaning of these words in the article already.

 

Comment 9: Figure 2 the authors are encouraged to provide clear information about the axis legends.

Response: Thanks for your advice. We have modified Figure 2 and the modified image is shown in Figure 2.

 

Comment 10: In subitem 3.2, the authors should prepare a figure summarizing the processing chain for clarity.

Response: Thanks for your advice. We have drawn an algorithmic processing flowchart as shown in Figure 5.

 

Comment 11: Lines 241-242: The authors should better explain this step..

Response: Thanks for your advice. We have explained this step in more detail.

 

Comment 12: Line 243: Do the authors mean the “regenerated” DEM or the original DEM after CFS filtering?

Response: Thank you for your question. This “regenerate” refers to the original DEM after CFS filtering of the DSM, which is in the form of a point cloud after CFS filtering due to the separation of non-ground points from the 3D point cloud, and needs to be rasterized into a DEM.

 

Comment 13: Figures 8 and 9: The legends of the graphs must be better presented. I suggest “along road” and “across road” instead of “the path of strike direction” and “the path of dip direction”.

Response: Thanks for your suggestion. We have modified the axes titles of these two plots as shown in Figures 9 and 10.

 

Comment 14: Figure 10: Please plot all curves in the same graph for comparison.

Response: Thanks for your suggestion. We have modified this image as shown in Figure 11.

 

Comment 15: Line 351: Use “Case study” instead of “Engineering application results.”

Response: Thanks for your suggestion. We have changed the name of Subitem 5.1.

 

Comment 16: Line 361: Explain the term “phase.”

Response: Thank you for your question. We have already explained the term “phase”in lines 435-437.

 

Comment 17: Figure 11: Clarify what the positive and negative values mean.

Response: Thank you for your question. We explain the meaning of the positive and negative values in Figure 12 in lines 437-438.

 

Comment 18: Line 363: Replace “deformation” with “displacement” throughout the paper. The terms have distinct meanings.

Response: Thanks for your advice. We have replaced “deformation” with “displacement” in the paper.

 

Comment 19: Line 373: Use “Accuracy assessment” instead of “Analysis of Sinking Extraction Results.”

Response: Thanks for your advice. We have changed the name of Subitem 5.2.1.

 

Comment 20: Figure 13 Legend: Accuracy assessment for different mining phases: a) phase IV direction E-W; b) phase IV direction N-S; c) phase V direction E-W; d) phase V direction N-S; e) phase VI direction E-W; and f) phase VI direction N-S. Please delete the legends below each graph.

Response: Thanks for your advice. We have replaced the legend below each figure in Figure 14.

 

Comment 21: Items 5 and 6: I encourage the authors to combine these into one item only. I suggest highlighting the pros and cons of the proposed algorithm. For example, what is stated in lines 408 and 432 is very interesting for those who plan to apply the method.

Response: Thanks for your suggestion. We have revised the “Discussion” and “Conclusion” sections. In the “Discussion” section we have highlighted the advantages and disadvantages of the algorithm. In the “conclusion” section we have emphasized the importance of the algorithm in practical applications.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Surface subsidence monitoring enables the timely detection of subsidence signs and trends, allowing for prompt action to effectively prevent and mitigate the impact of subsidence disasters. In response to this issue, this paper proposes a method to improve measurement accuracy by reducing the resolution of UAV photogrammetry with UAV model DJI Phantom 4 RTK.

This paper proposes deformation-adapted spatial domain filtering algorithm, which obtains a filtering grid by utilizing the slope values between sample points in the DEM, and then digitally averaging the settlement values of the sample points within the grid to obtain a processed DEM. This algorithm calculates the inclination values between adjacent sampling points in the original subsidence basin to determine the grid size for filtering. It then digitally averages the subsidence data within each grid by reducing the UAV resolution. Finally, optimizes the model using a noise reduction algorithm to construct the subsidence basin. The results show that this method significantly improves the accuracy of the subsidence basin.

This method improves by more than 50% compared to conventional methods. Also, this method reduced surface subsidence elevation errors by approximately 39% compared to existing methods. Furthermore, this study effectively addresses the issue of poor accuracy in UAV measurements caused by random error.

Please, define UAV, Unmanned Aerial Vehicles? Also, DEM, Digital Elevation Model? other abbreviations too.

Figures 4 - 7 could be in better resolution.

Figures 8 & 9: labels of 2 axes are not clear.

Figure 11: ordinate could be in better resolution.

Figure 12: missing units on axes.

Author Response

Comment 1: Surface subsidence monitoring enables the timely detection of subsidence signs and trends, allowing for prompt action to effectively prevent and mitigate the impact of subsidence disasters. In response to this issue, this paper proposes a method to improve measurement accuracy by reducing the resolution of UAV photogrammetry with UAV model DJI Phantom 4 RTK.

This paper proposes deformation-adapted spatial domain filtering algorithm, which obtains a filtering grid by utilizing the slope values between sample points in the DEM, and then digitally averaging the settlement values of the sample points within the grid to obtain a processed DEM. This algorithm calculates the inclination values between adjacent sampling points in the original subsidence basin to determine the grid size for filtering. It then digitally averages the subsidence data within each grid by reducing the UAV resolution. Finally, optimizes the model using a noise reduction algorithm to construct the subsidence basin. The results show that this method significantly improves the accuracy of the subsidence basin.

This method improves by more than 50% compared to conventional methods. Also, this method reduced surface subsidence elevation errors by approximately 39% compared to existing methods. Furthermore, this study effectively addresses the issue of poor accuracy in UAV measurements caused by random error.

Please, define UAV, Unmanned Aerial Vehicles? Also, DEM, Digital Elevation Model? other abbreviations too.

Response: Thanks for your question. We have already explained the meaning of these words in the article already.

 

Comment 2: Figures 4 - 7 could be in better resolution.

Response: Thanks for pointing out the question. We have replaced the higher-resolution figure in the paper, as shown in Figure 3-8.

 

 

Comment 3: Figures 8 & 9: labels of 2 axes are not clear.

Response: Thanks for pointing out the question. We have redrawn the axes headings in Figure 9-10 to make them clearer.

 

 

Comment 4: Figure 11: ordinate could be in better resolution.

Response: Thanks for pointing out the question. We have re replaced Figure 12 with a higher resolution figure.

 

Comment 5: Figure 12: missing units on axes.

Response: Thanks for pointing out the mistake. We have added the units on axes in Figure 13.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Paper "Deformation-adapted spatial domain filtering algorithm for UAV mining subsidence monitoring and its applications" presents a topic related to the mining and mining risks, in general.

 

Several suggestions will be emphasized:

 

-        The title should indicate which real case study it is about.

-        Commenting on the results should be avoided in the abstract. It especially refers to numbers, because they have no significance here.

-        Edit keywords. These should not be words from the title, but significant words from the abstract.

-        In the introduction, it is necessary to mention experiences from all over the world, in addition to those mentioned and limited to China.

-        The research area cannot be described in the Materials chapter. With such a title, more should be written about the input parameters, but only after the described Methodology.

-        It is necessary to create a new chapter where the research area is described. It would be very important to show geological units as well as a map or cross-section … because the abstract mentions ground subsidence/land subsidence.

-        It is necessary to add and discuss input parameters, related to geotechnical parameters ...

-        The methodology is briefly described without significant details. It is suggested to present the entire research process step by step.

-        Results should not contain equations. This is shown in the methodological procedure.

-        The discussion is too short and doesn't make any sense. It is suggested to link to the chapter where the results are. Thus, readers could more easily understand the presented diagrams and didcussion of those results. You really need to make some effort and write the discussion in more detail.

-        The conclusion is like a summary. Here it should be written briefly why the paper is worth publishing ... This refers primarily to the scientific contribution of the research carried out, and also to the importance it has for the academic community and engineering practice.

Author Response

Comment 1: The title should indicate which real case study it is about.

Response: Thanks for your suggestion. We have made changes to the title.

 

Comment 2: Commenting on the results should be avoided in the abstract. It especially refers to numbers, because they have no significance here.

Response: Thanks for your suggestion. We have explained the numbers part of the result in lines 465-467, showing that this result was obtained under the experimental conditions of this paper.

 

Comment 3: Edit keywords. These should not be words from the title, but significant words from the abstract.

Response: Thanks for your suggestion. We modified the keywords by replacing “Mining area surface deformation” with “Subsidence monitoring” and “accuracy improvement” with “Underground coal mining”.

 

Comment 4: In the introduction, it is necessary to mention experiences from all over the world, in addition to those mentioned and limited to China.

Response: Thanks for pointing out the question. We have added experiences from countries other than China's experience in the introduction section with literature citations.

 

Comment 5: The research area cannot be described in the Materials chapter. With such a title, more should be written about the input parameters, but only after the described Methodology.

Response: Thanks for pointing out the question. We have separated the overview of the study area from the chapter “Materials”. The problem of input parameters is more fully explained in the chapter “Principles and Methods”, and a flowchart of the process has been drawn up, as shown in Figure 5.

 

Comment 6: It is necessary to create a new chapter where the research area is described. It would be very important to show geological units as well as a map or cross-section … because the abstract mentions ground subsidence/land subsidence.

Response: Thanks for your suggestion. We have created a new chapter to describe the study area, which is presented in Chapter 2, “Overview of the study area”. At the same time, we have mapped the geographic location of the workface, as shown in Figure 1.

 

Comment 7: It is necessary to add and discuss input parameters, related to geotechnical parameters ...

Response: Thank you for your valuable comments. We recognize the importance of geotechnical parameters for the study of rock movement laws. However, the primary focus of this thesis is to introduce and validate the effectiveness of our proposed algorithm rather than to explore the rock movement laws in depth. Nonetheless, we did collect relevant geotechnical parameter data during our study and plan to explore the effects of these parameters on the rock movement laws in detail in subsequent work. In our next paper, we will focus on the geologic conditions of the study area and the facies distribution characteristics of the collapse zone, at which time these geotechnical parameters will be fully discussed.

 

Comment 8: The methodology is briefly described without significant details. It is suggested to present the entire research process step by step.

Response: Thanks for your suggestion. We have described the methodology part of the study in more detail, which can be shown in “4.3. Deformation-adapted spatial domain filtering algorithm”.  And the algorithm processing flowchart has been drawn, as shown in Fig. 5.

 

Comment 9: Results should not contain equations. This is shown in the methodological procedure.

Response: Thanks for pointing out the question. We removed the equations from the results section and added this section to “4.3. Deformation-adapted spatial domain filtering algorithm”.

 

Comment 10: The discussion is too short and doesn't make any sense. It is suggested to link to the chapter where the results are. Thus, readers could more easily understand the presented diagrams and discussion of those results. You really need to make some effort and write the discussion in more detail.

Response: Thanks for pointing out the question. We have carefully considered your suggestion regarding the discussion section and have decided to rewrite this section rather than linking it directly to the results section. In rewriting the discussion section, we have paid particular attention to the following points: (1) We have strengthened the interpretation and analysis of the results to ensure that the discussion is closely related to the results. (2) Consideration was given to possible limitations and future research directions to promote further research in this area.

 

Comment 11: The conclusion is like a summary. Here it should be written briefly why the paper is worth publishing ... This refers primarily to the scientific contribution of the research carried out, and also to the importance it has for the academic community and engineering practice.

Response: Thanks for pointing out the question. We have reworked the conclusion section to focus on what the paper mainly contributes and why it is worth publishing.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

·  Lines 2-4: Title: "Deformation-adapted spatial domain filtering algorithm for UAV mining subsidence monitoring"

·  Lines 21-23: This statement is unclear and requires rephrasing.

·  Lines 31-32: Avoid using keyword phrases like "adaptation to mining-induced deformation."

·  Lines 57-58, 89, 292, 329, 482 and 530: Clarify the distinction between "displacement" and "deformation."

·  Line 124: What do you mean by "extraction accuracy"? Please clarify.

·  Figure 1: Should be moved to follow subitem 2.2.

·  Line 185: Specify the model of the UAV used (DJI Phantom 4 RTK).

·  Line 200: Table 1 includes unnecessary details such as "graphic transmission technology" and “battery capacity”. Explain how this information is relevant or consider removing it.

·  Line 223: For Map 4, include in the legend the scale units, horizontal datum, and projection system.

·  Line 338: Use "settlement basin" or "sinking basin" instead of "sedimentary basin." Replace DOM with DEM.

·  Line 388: "comparison of path changes for different grid sizes."

·  Lines 415-418: These lines are unclear and need rephrasing for better understanding.

·  Line 420: "Surface settlement maps obtained through the proposed algorithm: (a) phase II; (b) phase III; (c) phase IV; (d) phase V; and (e) phase VI. Positive values represent surface subsidence”. Also, include the mining phases in these figures, as shown in Figure 13 as red rectangles. Eliminate the text after letters “a” to “e”.

·  Line 430: Consider eliminating Figure 13 due to redundancy.

Table 4 is not referenced in the text. Additionally, explain why RMSE values for phases I to III are not included.

·  Line 469: Clarify the citation "Javier Cardenal et al. (XXXX)"...

·  Line 472: “In contrast to the methods PROPOSED by Lian et al. (XXXX) and Zhou et al. (XXXX)”…

·  Line 456: The discussion section should be rewritten for clarity. Avoid quoting other authors, as this has already been addressed in the introduction. Instead, focus on the pros and cons of the proposed algorithm. Is the detected vertical displacement considered critical? Additionally, discuss the typical surface displacements induced by coal underground mining.

Comments on the Quality of English Language

Nothing to declare.

Author Response

Comment 1: Lines 2-4: Title: "Deformation-adapted spatial domain filtering algorithm for UAV mining subsidence monitoring"

Response: Thanks for your advice. We've had the dissertation topic revised.

 

Comment 2: Lines 21-23: This statement is unclear and requires rephrasing.

Response: Thanks for pointing out the question. We have rewritten this sentence more explicitly, as in lines 25-27.

 

Comment 3: Lines 31-32: Avoid using keyword phrases like "adaptation to mining-induced deformation."

Response: Thanks for pointing out the mistake. We have reworked this keyword.

 

Comment 4: Lines 57-58, 89, 292, 329, 482 and 530: Clarify the distinction between "displacement" and "deformation."

Response: Thanks for pointing out the question. In the text, the word “deformation” is used to characterize the deformation of the surface caused by mining, while the word “displacement” is used to describe the specific value of the change in the surface. The term “displacement” is intended to describe more the degree of deformation and the direction in which the deformation has moved, while the term “deformation” is intended to describe more the structural changes in the surface as it has moved.

 

Comment 5: Line 124: What do you mean by "extraction accuracy"? Please clarify.

Response: Thanks for pointing out the mistake. We have changed this sentence to be clearer, as in lines 134-136.

 

Comment 6: Figure 1: Should be moved to follow subitem 2.2.

Response: Thanks for pointing out the mistake. We have moved this figure to subitem 2.2.

 

Comment 7: Line 185: Specify the model of the UAV used (DJI Phantom 4 RTK).

Response: Thanks for pointing out the question. We have specified the model of the UAV in the text, as in line 250.

 

Comment 8: Line 200: Table 1 includes unnecessary details such as "graphic transmission technology" and “battery capacity”. Explain how this information is relevant or consider removing it.

Response: Thanks for your advice. We have removed irrelevant parameters from the table.

 

Comment 9: Line 223: For Map 4, include in the legend the scale units, horizontal datum, and projection system.

Response: Thanks for pointing out the question. We have reworked map 4 in Figure 1.

 

Comment 10: Line 338: Use “settlement basin” or “sinking basin” instead of "sedimentary basin." Replace DOM with DEM.

Response: Thanks for your advice. However, the words “sedimentary basin” and “DOM” do not appear in line 338 or in the adjacent paragraphs.

 

Comment 11: Line 388: "comparison of path changes for different grid sizes."

Response: Thanks for your advice. We have made changes in the text, as in lines 522.

 

Comment 12: Lines 415-418: These lines are unclear and need rephrasing for better understanding.

Response: Thanks for pointing out the question. We have rewritten this sentence more explicitly, as in lines 552-554.

 

Comment 13: Line 420: “Surface settlement maps obtained through the proposed algorithm: (a) phase II; (b) phase III; (c) phase IV; (d) phase V; and (e) phase VI. Positive values represent surface subsidence”. Also, include the mining phases in these figures, as shown in Figure 13 as red rectangles. Eliminate the text after letters “a” to “e”.

Response: Thanks for pointing out the question. We have modified the figures as well as the graphic notes.

 

Comment 14: Line 430: Consider eliminating Figure 13 due to redundancy.

Response: Thanks for your advice. Since the extent of the impact of mining is not reflected in Figure 12 is not obvious enough, Figure 13 is to make it more obvious that the extent of the impact of the subsidence basin has been affected.

 

Comment 15: Table 4 is not referenced in the text. Additionally, explain why RMSE values for phases I to III are not included.

Response: Thanks for pointing out the question. References to Table 4 have been reflected in the text, and explanations have been given for the absence of data for phases 1 to 3, as shown in lines 587-589.

 

Comment 16: Line 469: Clarify the citation "Javier Cardenal et al. (XXXX)"...

Line 472: “In contrast to the methods PROPOSED by Lian et al. (XXXX) and Zhou et al. (XXXX)”…

Line 456: The discussion section should be rewritten for clarity. Avoid quoting other authors, as this has already been addressed in the introduction. Instead, focus on the pros and cons of the proposed algorithm. Is the detected vertical displacement considered critical? Additionally, discuss the typical surface displacements induced by coal underground mining.

Response: Thanks for pointing out the question. The combination of the Discussion section and the Result section, which has been made available in the article, has been added to the RESULTS section as there are fewer DISCUSSION sections, which will make it easier for the reader to understand the graphs presented and these results. At the same time, the references to other authors have been removed from the text and the advantages and disadvantages of the proposed method have been added, such as lines 500-506 and lines 609-630.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have made an effort to improve the quality of scientific paper. A few more suggestions will be added.

 

 

-        In chapter 2, transfer the map of the study area, which is in chapter 3. Because as the title says, in chapter 3 are the input parameters.

-        Chapter 5 has many subchapters; Eg why the title again - case study?

-        I still think it would be easier for readers to understand if chapters 5 and 6 were harmonized into one.

-        In the conclusion, which is in the form of a summary, add a clear scientific contribution of this research.

Author Response

Comment 1: In chapter 2, transfer the map of the study area, which is in chapter 3. Because as the title says, in chapter 3 are the input parameters.

Response: Thanks for pointing out the question. We have moved this figure to subitem 2.2.

 

Comment 2: Chapter 5 has many subchapters; Eg why the title again - case study?

Response: Thanks for pointing out the question. We have made changes to the title.

 

Comment 3: I still think it would be easier for readers to understand if chapters 5 and 6 were harmonized into one.

Response: Thanks for your suggestion. We have combined the Discussion section with the Result section, as in lines 500-506 and 609- 630.

 

Comment 4: In the conclusion, which is in the form of a summary, add a clear scientific contribution of this research.

Response: Thanks for your advice. We have rewritten the Conclusion section to make the scientific and explicit scientific contributions of this method more apparent.

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