Evaluating the Feasibility of Illegal Open-Pit Mining Identification Using Insar Coherence

Round 1

Reviewer 1 Report

Good paper, and very valuable contribution to research community.

Author Response

Dear reviewer:

 

  Thank you so much for your appreciation to our paper!

 

Kind regards,

All the authors

Reviewer 2 Report

The topic of the paper is indeed interesting and timely, but the manuscript should be improved before publication. Some points to be addressed:

Section 1. Authors should mention that, apart from weather conditions, sun illumination is another important impediment to the regular use of optical imagery. Line 61. Authors mention that underground mining activities induce “slow” subsidence. This is not true. Underground mining activities can induce abrupt (and harmful) surface deformation phenomena. Lines 65. Authors should add a bibliographical reference when they introduce “off-set tracking” techniques. Line 73. Reference [18] see inappropriate. Section 2.3. Authors insist on the concept that decorrelation is due to fast motion. This is at least questionable in open-pit mines. Decorrelation is due to reflectivity changes induced by the mining activities. The number, the characteristic, as well as the spatial distribution of the scattering centres within each SAR pixel corresponding to an area subject to excavation change severely, inducing decorrelation. Authors should describe the size of the estimation window for coherence estimation as well as the multi-looking that they are performing. Since they apply Otsu’s algorithm, authors should report the histogram of the coherence maps. Authors should comment on how they decided the parameters of the median filter and whether this makes sense in this application. The quality of Figure 4 is not very good. Difficult to read.

Hope this can help improve your paper.

Author Response

Dear reviewer,

  First of all, thank you for your valuable advices. This paper definitely will benefit a lot from those advices! And I have made some modifications accordingly. Please see the attachment.

Kind regards,

All the authors.

Author Response File: Author Response.docx

Reviewer 3 Report

The paper shows the practical implementation of a known technique to detect illegal mining activities. Although it is not innovative, it does show the applicability of the technique, and its interest lies on that. 

The paper would benefit from reordering to increase its readability. Even more, I have the feeling that authors sometimes took too much information for known, which is understandable when one spends long time in a subject, but still has to be done. Figures are difficult to read, too. Theoretical background of the method is too narrow in some points.

Conclusions should address more widely some of the issues or problems of the technique. 

 

Comments for author File: Comments.pdf

Author Response

Dear reviewer:

  Thank you for offering so many valuable advices. This paper definitely will benefit a lot! And  I’ve made some modifications accordingly to this paper. Please see the attachment.

Kind regards,

All the authors.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The paper has been significantly improved compared to previous version. A fewminor remarks:

In general: Review the English

Line 129 – Errata: Geometric decorrelation is caused by topographic impact, such as overlaying and shadowing effects. Corrige: Geometric decorrelation is caused by changes in the looking angle of the sensor, causing the acquisition of non-overlapping bands of the ground wavenumber spectra (Gatelli et al., 1994).

Use of the expression “Coherence coefficient” - Lines 150: Errata: “Coherence coefficient” Corrige: “Coherence map” or ”cross-correlation coefficient”.

Add information about the typical extent of a mining area based on the mining rights map for Ordos.

Mention possible improvements of the methods, e.g. use of VH data rather than just VV.

 

Author Response

Dear reviewer,

 

  Thank you for your approval to our work, and we have made several revisions according to your latest review comments. Please see the attachment.

 

Kind regards,

All the authors.

Author Response File: Author Response.docx

Reviewer 3 Report

There were some problems with the uploading of the review. Please proceed with the review according to the attached file.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

 

  Thank you for providing the right version PDF with so many valuable advices. We have proceeded with it and all the comments as well as advices have been accounted for. Please see the attachment.

 

Kind regards,

All the authors.

Author Response File: Author Response.docx