Remote and Proximal Sensing-Derived Spectral Indices and Biophysical Variables for Spatial Variation Determination in Vineyards

Round 1

Reviewer 1 Report

Remote and Proximal Sensing Derived Spectral Indices and Biophysical Variables for Spatial Variation Determination in Vineyards
Dear Authors,
it is a great pleasure for me to be able to review such a good work. In fact, I have included only a few minor comments.
A great advantage of the work is the clear way of conveying the content, good discussion, clear presentation of research results. You can see that it was prepared by professionals.
The only drawback of the work is the fact that the research comes only from one growing season. 
Please consider some minor remarks:
Abstract:
Why are remote sensing measurements "critical" ? I think you mean "crucial" or "important". Please correct this sentence.
Introduction:
Please provide information on the share of vineyards in the crop structure in Peloponnese.
Line 139-143. I suggest moving this part of the work to the conclusion.
Materials and methods: Yield estimation and Statistical analysis
Did each of the separate sample blocks have the same area? If so, please add this.

Author Response

Thank you very much for your kind words and your fruitful comments.

We have tried to address all of them. More details you can find in the attached file.

Thank you once again for your efforts

Author Response File: Author Response.docx

Reviewer 2 Report

In general terms, the paper has severe flaws in formatting and style of writing. Although the results look very good and interesting, it is hard to follow the paper. Therefore I will suggest performing some modification to improve the paper in order to highlight the value of the authors’ efforts. Following, I include some modifications that must be done before reconsidering the paper:

• The abstract must be reduced according to the journal specifications. Moreover, I suggest avoiding the use of acronyms in the abstract if possible. Authors have to set the problem in just 1 or 2 lines (currently, they use 6). Authors use most of the abstract to detail their methodology. This must be enhanced. Authors must include only the most important (and novel) aspects of their methodology in the abstract. Then, they will have enough space to detail their results and conclusions in the abstract. If possible, I recommend including “numbers” when summarizing the results.
• I suggest splitting the introduction into 2 sections, introduction and state of the art. Thus, authors can focus on the problem they are trying to solve and detail the aim of the paper (in a single paragraph at the end of the introduction) in the introduction. In the state fo, the art authors can describe the existing solutions and highlight their paper’s novelty compared with the published solutions.
• In general terms, the paper is composed by long sentences, which difficulties the reading. In several cases, authors include a lot of acronyms. Some of those acronyms are not used again in the text, or they are used just a couple of times. For example BOA line 172 just used this time, SAVI in 251 or ACPA in 303. Moreover, in other parts, they have paragraphs composed of a single sentence. Authors must proofread the paper carefully, trying to make it easier to be read.
• The scientific names such as Vitis vinífera must appear in italics.
• Format issue: Most of the Figures and equations appear in the paper with a contour that has no reason to be there. Authors must remove this contour to keep the format of the journal.
• Format issue: Authors must check the quality of all the elements inserted in the figures. For example, Figure 1 c) has low quality, and the figure's text is too small to be read in the printer version. Please check all the Figures.
• Format issue: In all the legends of maps the units must be added. Check Figure 2 a) there is no “m” in the legend. In Figure 2 b), not all the colours of the legend have a tag.
• Atuhros named de bands as B1, B2…but in the equations, they use pb6 to refer to B6. They have to define pb6 in the text before using it in the equations. There are other issues in the equations that composes Table 2. First of all, they should be introduced as equations not as a table. Secondly, all the equations must be cited in the text as (1), (2), …
• Table 3 can be included as a Figure, making it easier to read it and understand the variations measured. Although there are many possible option for presenting these data, I suggest using box-whisker plots. This is just a suggestion author can use other plots. If authors want to keep it as a table, they must correct the table's format according to the journal template—same comment for the first Table 4.
• There are two Table 4; the second one is again composed by equations (as Table 2). I suggest evaluating the options of changing the way in which equations are presented. Since they are included in the regression models below, ig authors just want to show the accuracy of each model. They can include just this info and, if possible, include p-value, correlation coefficient, R2, and MAE if they consider that it can be interesting. All these terms are calculated by statgraphics.
• Concerning the regression models, Figure 6, authors must define what the green and grey lines in the figure (the intervals) are. Moreover, there are blue and grey squares; authors must define the meaning of each one. In addition, authors must justify why they focused on linear regression models instead of exploring other models' possibilities. The “Plot of Fitted Model” must be deleted from all the captures.
• In Figure 7 "Stages” must appear in a single line. Besides, authors should evaluate other format options since it is impossible to read any value of the figure—same comments for Figure 8.
• The discussion section should be divided into two or more sections focusing on the essential aspects of the discussion.
• The conclusions section should include a paragraph detailing future work linked to their findings.

Author Response

Thank you very much for your fruitful comments.

We have tried to address all of them. You can find more details in the attached file

Thank you once again for all your efforts

Author Response File: Author Response.pdf

Reviewer 3 Report

The work is very interesting and well done. All sections are well-curated and all information well structured.

Two main problems emerged:

• Low, medium and high yield map classification. The differences between the minimum and maximum values ​​of the vegetation indices are very small. The subdivision of the areas made with quantiles should be supported by statistical analysis. How is it possible to subdivide such narrow values ​​of VIs in a statistically significant way? what was the difference in the value of the indices among the 3 zones?
• Furthermore, given the VIs results in variability in the different phenological phases, how do you suggest a tool (the right VIs and date) during the growing season that can be realistically used without the support of researchers and field data?

Author Response

Thank you very much for your fruitful comments.

We have tried to address all of them. You can find more details in the attached file

Thank you once again for all your efforts

Author Response File: Author Response.pdf

Reviewer 4 Report

The first thought that popped to mind upon reading the paper’s title was that probably the authors would present some new vegetation indices (VI) or methods and then proceed comparing them to well-established ones to enable a swift evaluation of both precision and effectiveness. However, the abstract section is very objective and is quick to enlight users to the paper’s purpose: to compare to types of monitoring approaches by comparing well-know VI and biophysical parameters in a vineyard context. This seams more a work that tries to consolidate present knowledge than otherwise. Although with a lesser degree of innovation and recognizing the extreme variability of vineyards in some geographical contexts, this work may be very useful to provide a solid base in acquiring data and producing relevant information for farmers.

 

The document is generally well written and it is ready to understand. However, some of it is written is what can be classified as loose sentences, without sufficient flow to the next sentence so that it can be considered a text (e.g. the first few paragraphs of the introduction). Some phrases are also without meaning (e.g. lines 66, 67 and 68, line 119 onward). This should be addressed having a detailed language revision done, which would further improve the document’s readability. Still regarding the introduction, the statement made in line 71 - “almost everyday acquisition” - should be clarified. Which satellite is this? The one the authors use has a 5 day acquisition frequency, so it is not clear. Lastly, the last paragraph that presents the paper’s contribution referring to yield estimation use freely available tools and data needs some clarification. Whereas data can be accessible, farmers do not generally possess the knowledge to process it and extract valid information. As such, whilst it may be used as the authors proclaim, this paper does not present a tool or a way that enables the general public to obtain their own valid and useful information.

 

Chapters 2 and 3 follow the rule of so many papers presented in this research area. They are fine and show the readers how were the studies done in detail and the data that was acquired.

 

Whilst chapter 4 does seam to be fine, there is a phrase that needs to be rewritten: lines 462 to 465. Indeed, what is a “very high spatial resolution”? Today, a 2cm pixel is already possible with UAVs without any issue and using different coupled sensors. There are also satellites (while with images not completely available to the public) that are able to acquire 50X50 cm pixels. Please provide more detail about what the intention is.

 

Conclusions are what they are. They seam fine. However, this seams to be indeed a consolidation work, without any significant new contribution to what is being done in this area. If there is such a contribution, it is not sufficiently clear to understand.

Author Response

Thank you very much for your fruitful comments.

We have tried to address all of them. You can find more details in the attached file.

Thank you once again for all your efforts.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have addressed the comments, and the paper is now suitable for being published.

Reviewer 3 Report

The authors edited the manuscript in accordance with the reviewers' requests

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.