Applying Close Range Non-Destructive Techniques for the Detection of Conservation Problems in Rock-Carved Cultural Heritage Sites

Round 1

Reviewer 1 Report

Dear authors, I have reviewed the manuscript “Applying close range non-destructive techniques for the detection of conservation problems in rock-carved cultural heritage sites” authored by Frodella, W.; Elashvili, M., Spizzichino, D.; Gigli, G.; Akaki Nadaraia, A.; Kirkitadze, G.; Adi-kashvili, L.; Margottini, C.; Antidze, N.; Casagli, N. (remotesensing-1109623). I have enjoyed reading it.

I think that the paper includes an interesting amount of work (both at field and at lab) and your results are of great interest for the proper conservation of such impressive heritage places although extremely susceptible.

Anyway, I think that the paper lacks technical data about the IRT and UAV-DP surveys. You should add that information. Not only about the instruments, but also about the applied methods and results (final products: DEM, orthoimages, …). You should give information about the data acquisition and reduction method, errors, etc..

Moreover, the figures have to be improved since it is difficult to see some data because the font sizes, bright colors, white letters on bright backgrounds (maybe a solution is that text be included in a box with a filled background), small sizes of some images, legends are not clear, etc. In the case of the hydric networks overlaid on the images, the chosen colors do not contrast with respect the image background. This is a general comment to most of figures.

Finally, please check the reference list and their position in the main text since I think that some of them are not properly arranged or numbered.

I have added a pdf with some comments to text.

Comments for author File: Comments.pdf

Author Response

As a general comment we are grateful for both reviewers’ comments. We carefully carried their accurate revisions, thanks to which we believe that the quality of the paper has much improved. English was edited by a native speaker and the quality of the figures was improved (we have had a problem with low resolution files during the submission, we hope we have solved that). We believe that one of the key element of this paper are the figures; almost all of them are complex (being mosaics), so it was a big challenge to make them as clear and readable as possible for the readers. We think that they can be better appreciated if in full page size, so we have enlarge most of them. Consequently the whole paper has been re-formatted. Furthermore, we have improved their clarity enhancing their sharpness, and increasing the size/border thickness of the letters borders. Figure 5 was added during this revision (sorry, it was missing from the first submission). Many figure captions had mistakes that were corrected. The reference list was also corrected and its order re-arranged (6 self-citations were deleted).

Response to Reviewer 1 Comments

 

I would like to thank rev#1 for his encouraging comments and his accurate revisions (especially in the reference list section). I am glad he found our work pleasant to read, in my opinion this is the best compliment an author could have, since to catch the readers’ attention should be one of the most important targets when writing a paper (even a scientific one).

 

Hereafter we’ll provide a point-by-point answer (tracked in red), trying to carefully fulfill all of his comments

 

Reviewer 1 comments/answers

 

Point 1: line 57 uniaxial compressive strength. Since UCS is used along text, please indicate here the acronym (I think it is the first place where it must appear). Then you can use only UCS

 

Response 1: You are right, thank you. We have introduced the acronym as requested.

 

Point 2: line 62-66 Are references [12] and [13] correct here?

 

Response 2: Yes, they are correct, since [12] is a reference work on geomechanical parameters of rockmass discontinuities (including aperture), and [13] shows a clear example of “rockmass discontinuity network are areas of preferential of rainfall infiltration and seepage, enhancing concentrated erosion”

 

Point 3: 275 “rock samples” is repeated

 

Response 3: the term was deleted

 

Point 4: 306-307 “(FLIR, 2015) [43].” “[44]”. Are these references, 43 and 44, correct? Are not they 62 and 63?

 

Response 4: we are sorry for the mistake, the correct reference are as you reported 62 and 63

 

Point 5: 308 In Table 1, Instead of: “Image res.(px)” use camera resolution (pix) “Im res (cm)” , use “Image resolution (cm)”And can you indicate what Rh (%) is?

 

Response 5: the terms were corrected as requested (Rh stands for Relative humidity). We think that now the table is more clear

 

Point 6: 310 “DP is a well-established and low-cost technique…”. It is OK and I agree, but the “low cost” depends on the instrumentation and photogrammetric workstation you use. There are photogrammetric methods that are not

low cost at all.

 

Response 6: We agree that this statement is not correct, therefore we have erased “low-cost” from the text.

 

Point 7: 317 References 66 and 67 are not mentioned. Is reference 69 pertinent here? (since this sentence, 315-316, is about UAS applications)

 

Response 7: You are right, 69 was moved to line 314 and its order changed to 66, therefore 66 and 67 will move to 67 and 68 respectively, and are quoted in line 316. Changes in the reference list were made accordingly.

 

Point 8: 309 Can you give information (table, figure, short paragraph, instruments – camera and TLS- errors, image resolutions, product resolutions,…) about the UAS and TLS survey and the generated products? You mention only

the UAS platform

 

Response 8: several details were added to paragraph 3.3 (see lines 321-338), a new reference [71] and a new table was added, showing technical information on the adopted devices and the obtained resolution of the DSM.

 

Point 9: 335-346 This long paragraph could be split in different indented lines for each item/formula. I think it would be clearer to read. Even a table could be an alternative

 

Response 9: thank you. We opted for your first proposed solution

 

Point 10: 364 I think that reference 79 in text is wrong (¿78?)

 

Response 10: by adding [71] now 79 is correct

 

Point 11: 367 “The Georgian rupestrian monastery complexes of and David Gareja”

Correct?

 

Response 11: Correct (…and… deleted)

 

Point 12: 393 Add on figure caption: “Figure 6. Structural setting and kinematic analysis at Vanis Kvabebi:…”

 

Response 12: The Figure caption was added as suggested.

 

Point 13: 414 Figure 7. Please add next to each highlighted oval in Fig 7a the image code b, c, d or e.

 

Response 13: The Figure was modified as suggested

 

Point 14: 420 Instead of “6.5 cm pixel resolution” it is better 6.5 cm image resolution or 6.5 cm pixel size

 

Response 14: we agree, pixel resolution was changed into “pixel size”

 

Point 15: 434 Figure 8. Is the temperature profile in 8b the dashed line represented in 7a and marked with Li1? If so, please indicate that. If not, explain what Li1 is or delete it and indicate where the profile 8b in 8a is. What is the large white dashed rectangle in 8a? Please add a rectangle in 8a indicating where are the sectors 8c and 8d.

 

Response 15: specifications in the figure caption were added regarding Li1 profile (b), The white rectangle in (a), which represents the 2017 collapse area (Area Of Interest 1=AOI 1), which is shown in (c). (d) is located in the cliff southern sector, and is not represented in Fig. 8a.

 

Point 16: 438-452 Please, could you give information or add a RGB image about where are de areas represented in Figure 9? Please explain in the figure 9 captions what represent the different colours in the images. Are the “red ovals” (in text), the white ovals in fig 9c

 

Response 16: you are right, we have added in the text a reference on the area examined with the kinematic analysis, which is the cliff area represented by the 3D model in Fig. 2b. To explain better the figure we have added the following sentence in the text (lines 468-472): “the color scale represents the 3D spatial probability of occurrence (expressed in %) for the different instability mechanisms, with colors ranging from blue (very low proba-bility) to red (high probability), for the most relevant detected instability mechanisms confirmed the main identified instability mechanisms affecting the rock cliff”. There was a mistake in the caption, which was corrected, the “red ovals” are of course the “white ovals” in fig. 9c. Both ovals (Niche 1 and 2) were explained in the text with reference to previous figures (see lines 474-477).

 

Point 17: 493-497 Figure 11. Indicate explicitly AOI2 and 3 in the figure caption

 

Response 17: the figure caption was modified accordingly

 

Point 18: 509-510 “Figure 12. 2D kinematic analysis at Sabereebi: Wedge…” Indicate in the figure caption the location

 

Response 18: sorry, the caption was incomplete: the description of the top figure part was missing. We have corrected it (see lines 538-540)

 

Point 19: 528 Indicate in the figure caption what area represents this figure. Legends of the slope values are not clear, as well as the drainage patterns colours

 

Response 19: the figure (c) represents, as the cation says: “UAV close- up on the detachment sector showing light brown colored mud drips on the dark brown sandstones”. We have modified the legend and changed the figure settings in order to enhance the drainage pattern colors. We hope that now the figure will be more clear.

 

Point 20: 565 and 592 Values for temperature in the box of figure 16b are not clear at all. The same for figure 17d/h. Moreover, Figure 17 seems to be out of its correct place before section 5 Discussion.

 

Response 20: the size and sharpness of the box in fig. 16b were increased, as well as for Fig.17, that was placed before the discussions.

 

Point 21: 584 Can you avoid using the reference beginning the paragraph? It is better to rephrase the sentence

 

Response 21: the sentence was refrased (see line 608)

 

Point 22: 591 Does this comment to the Bamiyan site need reference?

 

Response 22: we agree, both Lalibela and Bamiyan sites are out of the scope of this paper.

 

Point 23: 615 Is reference 18 correct in this sentence? [18] refers to the UNESCO WH List

 

Response 23: there was a mistake: the correct reference in the sentence is 13

 

Point 24: 625-629 Please check the references 85 to 87. They appear in different order in text or in the reference list. I suppose that Nichols (2009) which first appears in line 627 should be [85], not [87] (it is a text book about Sedimentology and it matches to the sentence in lines 623-626

 

Response 24: it’s correct, sorry for the error in the numbering of the reference. Nichols (2009) was moved to [85]

 

Point 25: 676 Figure 18 caption. Can you check the colours of the rectangles? I think that red rectangles are the cliff areas and black rectangle (it is not shaded) is the area represented in 18b. Is the figure caption incomplete? Is the planned wall the dashed red line?

 

Response 25: you are right, sorry for the mistakes in the caption; it was corrected according to your suggestions (see lines 695-697)

 

Point 26: 711-713 Check the letters a, b, c, in the figure caption. The figure has only images.

 

Response 26: the missing letters a,b,c were added to fig.19

 

Point 27/28: 721 The reference [90] is not in the reference list/724 Reference [87] does not match here

Response 27/28: there was a mistake in the order of the final references; it now corrected (see references from 88 to 90)

 

REFERENCE LIST

 

Point 29: Is reference [58] complete?

 

Response 29: the number of pages (77-84) was added.

 

Point 30: Check the references in text for [66] [67] [68] and [69]

Response 30: referenced checked (see point 7)

Point 31: Check for reference [90] in text

Response 31: the reference [90] is now in the caption of Fig. 20

Reviewer 2 Report

Some general comments: 

There is real need for editing of the English text. Make uniform (American-English or UK-English), quite some typos, words missing, ununderstandable phrases, etc. For some details please check the version I provide here

There are quite some legends mentioning subparts that are not in the legend or mentioned in the text but not represented in the image that is provided.

It is a long paper (27 pages). Well-balanced however. But in my opinion, the quite long parts (in part 4) are more adequate in a  journal on geomechanics, geology etc. than in Remote sensing. I am afraid this very technical (too) specialised paper will not get the audience it merits in my opinion.

I have made a remark on self-citations, as 21 on 89 references in the notes (i.e. 256%) are from on or another of the authors of this paper. Generally, esp. in the introductory part, it is possible to use some other references.

Comments for author File: Comments.pdf

Author Response

As a general comment we are grateful for both reviewers’ comments. We carefully carried their accurate revisions, thanks to which we believe that the quality of the paper has much improved. English was edited by a native speaker and the quality of the figures was improved (we have had a problem with low resolution files during the submission, we hope we have solved that). We believe that one of the key element of this paper are the figures; almost all of them are complex (being mosaics), so it was a big challenge to make them as clear and readable as possible for the readers. We think that they can be better appreciated if in full page size, so we have enlarge most of them. Consequently the whole paper has been re-formatted. Furthermore, we have improved their clarity enhancing their sharpness, and increasing the size/border thickness of the letters borders. Figure 5 was added during this revision (sorry, it was missing from the first submission). Many figure captions had mistakes that were corrected. The reference list was also corrected and its order re-arranged (6 self-citations were deleted).

Response to Reviewer 2 Comments

 

We thank again rev#2 for his accurate revisions.

Some general comments:

Thank you for your corrections of the English, (many of them were typing errors, more than language errors). In any case we have carried out in full your comments, plus the manuscript was revised by a native English teacher.

We are sorry for the legends and the figure captions, there were many errors (often shared with rev#1) that have been corrected.

We agree that the paper is long, but as you stated (and we take it as a big compliment) it is well balanced. We think that this is due to the fact that many interesting case studies were examined, all of them sharing common features (rock-carved cultural sites in soft rocks from the UNESCO world heritage/tentative lists, showing conservation issues such as instability/deterioration), and all of them investigated with close-range remote sensing techniques. We think that each case study shows a different methodological application and a different result, therefore giving interesting hints for protection strategies and the planning of future mitigation measures, so that’s why we have included them all. We see your point on part 4, a very important section such as the results, and that you found too specialized and more adequate for a journal on geomechanics etc., but we think that the core of the paper is the application of the close-range remote sensing techniques, and that the remote sensing readers are getting more and more used to geology/geomechanics, since many colleagues working in my field have been publishing in the last years on this journal. In light of this, we hope that our paper can fit as an original contribution in the special issue “Protection and Conservation of Cultural Heritage: A Role for Remote Sensing”, and that the readers of the journal will find it interesting.

We see your point again on the too many self-citations: as you can see the authors are formed by a team of Italian/Georgian experts working in different agencies. Amongst these Claudio Margottini (former scientific attaché at the Italian embassy of Egypt) is a well-known expert in cultural heritage protection from geological problems, with several decades of experience. He has worked on similar case studies (often with Daniele Spizzichino) in many parts of the world besides Georgia (Afghanistan, Ethiopia, Middle East, Egypt, South America, etc), so we thought that a strong reference to his works would have added a sound background to the paper. While Mikheil Elashvili’s works, he is a georgian engineering geologist with many years of experience on Georgian cultural heritage, on which geological background there is not a vast literature. The same thing for William Frodella, who is recognized internationally as an expert user of IRT (on which again, there is not a vast literature background, considering the geological applications). The team has shown an experience in dealing with the geological problems of georgian rupestrian heritage (especially in the site of Vardzia, which is geologically very close to Vanis kvabebi), so that’s the reason for the high number of self-citations. Anyways we agree to use other references in the introduction as you suggested, therefore 6 self-citations were substituted with other works in the reference list.

Round 2

Reviewer 1 Report

Dear authors, thank you for your efforts to improve the paper and following all reviewed points.

Regards