Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy

Round 1

Reviewer 1 Report

Under the scarcity of mineral resources and the increasing importance of the rare earth elements, the article entitled “Inversion Evaluation of Rare Earth Elements in Soil by Visible-2 Shortwave Infrared Spectroscopy” give some new perspective related to the analyse of these elements.

The article is focused from the point of view of the pollution, although in a close future, polluted soils with rare elements can be a source of them. In this way, the quantification of their presence has two possible reads: checking pollution and possible ore of rare earth elements.

In general, authors have shown in a very easy way a complex research and joined it with hyperspectral images (CASI/SASI). In my opinion, this article is of great interest.

Some suggestions with the idea of improving the article:

Line 18: “264 soil samples were collected and analysed” instead of “264 soil samples were collected”

Check the position of the hyphens at the end of the line, just to make easy to read the word. For instance, in line 21: “scatte-ring”  instead of “scatter-ing”. Check also the following lines: 52, 67, 98, 120, 207, 309,

Line 81: please check this “FWMH of about 81 20nm-80nm,”; The first time an abbreviation is used (FWMH), it is a good idea to write its meaning completely. Also, please check if the indicated wavelengths are correct.

Line 144: check this sentence, I am not sure about what you want to say, “The perdition results were depending on the pretreatment steps of reflection spectrum to some extents”

Line 146: “Savitzky-Golay filtering was used for spectral smoothing”. In my opinion, we have to be so carefully when using smoothing because some information can be lost.

I suggest to add some references when describing the effects of each transformation applied to know how the transformation is (points 2.31. to 2.3.5). The same suggestion can be applied when writing about PLS, RF and BPNN. Although it is not necessary to wrte all the mathematical formulas of each method, it would be of interest to have a citation where readers can follow and know the basement and mathematics behind each transformation and machine learning models. Surely, some of them are in previous paragraphs.

As a conclusion, I believe that authors would recommended a procedure based on BPNN after FD transformation as a methodology to detect rare earth elements (of course starting from the soil sample preparation technique to the quantification of the elements). This is a good achievement.

I think that during the editing process, tables and figures will be checked and organised adequately within the text.

Author Response

Dear review:

Thank you for your letter concerning our manuscript entitled Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy (ID: remotesensing-1470272). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to us. We have studied comments carefully and have made corrections which hope to meet with approval.

Author Response File: Author Response.docx

Reviewer 2 Report

The ms remotesensing-1470272 with the title of Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy is well written and organized. Below are my comments:

L 18: leave space between the values and the unit (400nm-2500nm). Please check this issue within the whole ms. Same in L110 300km2 etc.

Sections 2.3.1 – 2.3.5. can authors add references for these, if there are?

The authors have to add references for the described methods in the material and methods.

Did the authors made statistical analysis? Which program was used?

Please try to revise the conclusion, by making it stronger and straight.

Figures are very good presented as well as Tables.

The authors used very recent publications for citing references in the ms.

Regards, reviewer

Author Response

Dear review:

Thank you for your letter concerning our manuscript entitled Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy (ID: remotesensing-1470272). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to us. We have studied comments carefully and have made corrections which hope to meet with approval.

Author Response File: Author Response.docx

Reviewer 3 Report

See attached file

Comments for author File: Comments.pdf

Author Response

Dear reviewer:

Thank you for your letter concerning our manuscript entitled Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy (ID: remotesensing-1470272). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to us. We have studied comments carefully and have made corrections which hope to meet with approval.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

In the present shape article may be published.