Impact of Power on Uneven Development: Evaluating Built-Up Area Changes in Chengdu Based on NPP-VIIRS Images (2015–2019)

Round 1

Reviewer 1 Report

The submission proposes to extract urban built-up areas from 2015 to 2019 based on NTL, NDVI, and LST data for capturing the temporal-spatial characteristics in Chengdu. I have some major remarks:

1. The literature review is not enough, I missed a lot of important studies which use NTL to extract urban built-up areas; they should be discussed in more detail.
2. What are the research gaps/questions? It’s not clear to me.
3. Which version of the NPP-VIIRS data do the authors use?
4. Please do provide more details about the training set, validation set, and test set are for the SVM model. How were urban areas sampled exactly and in what regions? It would be very helpful to also visually illustrate the choice of train/val/test areas in the displayed regions.
5. Line 164-175: The SDE is conducted on NTL data or extracted urban areas? Line 172: what are the urban economic elements? So confusing.
6. Line 202-203, how did the authors extract the urban area from Landsat-8 and MODIS LST data? Please give more details. Why the extracted results can be considered as reference data?
7. The conclusion part needs considerable improvements. Please state the most important outcome of your work, do not simply summarize the points already made in the body. Try to interpret your findings at a higher level of abstraction. Also, at the end of your Conclusion, consider including perspectives.
8. Language issue: the language should be seriously proofread by a native English speaker.

Author Response

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Reviewer 2 Report

This paper employed stratified Support Vector Machine method to extract urban built-up area based on the Nighttime stable Light, Normalized Difference Vegetation Index, and nighttime Land Surface Temperature data to capture the spatiotemporal characteristics in Chengdu, China. From the data and methods side, this paper is lack of innovation, and the organization of this paper also has some issues.

1. Please check through the grammar and writing:

• Spelling: rang-ing; extract-ed; calcu-late (the last paragraph of Introduction section); please double check the whole paper.
• For the acronyms, please check through the whole paper carefully. Please only use the full name for the first appearance, then use the acronym after that. For NASA, SVM, SDE, and others, please carefully check through the whole paper.
• Be consistent: m (meters), km (kilometers). Please choose one and be consistent throughout the whole paper.

2. Methodology Section:

• Data section should be separated from the Study Area.
• Please draw a workflow to include the data and methods you used to help readers follow easily.
• Figure 1: change Miles to Km
• Table 1: it is very hard to see the contents of the figures in this table. Please change this representation.

3. Figure 8: this is not a map which missed all the essential map elements.
4. Table 5 has the same issue as Table 1. Please redo and reorganize these figures.
5. Section 4 & 5 can be combined, which are very general. Please improve. If you separate the two sections, Discussion should be first, then the Conclusions.
6. Please improve the resolution of all the figures such as Figure 1…

Author Response

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Reviewer 3 Report

Dear Authors,

 

The study is potentially interesting and written well. But I would like to suggest the following list of revisions to the manuscript to improve the quality of the manuscript

 

Major comments

1. Research methodology is not very clear for the readers. Therefore I would like to suggest of having a flow chart with all required input, methods, and output
2. You have used SVM machine learning algorithm to extract urban built-up area. How about using other machine learning algorithms to extract urban built-up area? Sometimes the accuracy may higher with other algorithms than SVM. Justify your selection
3. How many reference points employed to measure the accuracy of your classification? The information about reference points are very important to discuss about the accuracy
4. Objectives of the study is not clearly not described in the text
5. Originality of the study is not clearly not described in the text
6. The geometric setting of the study area is not clear. I am suggesting to properly define the study area
7. Figure 4, Figure 5: Is this for 2019? If so how about other years?
8. Why discussion after conclusion?
9. No information about cloud coverage of the satellite data and its impact on the accuracy
10. Metadata of the secondary data should be clearly described in the text

 

Minor comments

1. The quality of the maps needs to be improved
2. The English of the manuscript needs to be improved. There are few incomplete sentences, grammatical mistakes, and wording issues exist (e.g. LN 121-123, LN 134, LN 155, LN 156, LN 161 – 163, LN 297)
3. Table 1: North arrow and scale of the maps should be displayed
4. Table 2: North arrow and scale of the maps should be displayed
5. Some abbreviations are there without prior define (e.g. LN 141 MVC)
6. Figure 8: How about other map elements? The map is not complete
7. Table 5: Maps and graphs are not clear. Map elements should be there
8. Projection/coordinate system should be clear mentioned in the first map (study area)
9. Table 2: What green color is representing? A legend should be there
10. Did you employ any correction to satellite data sets?

  

The study is interesting and written well. Even there are few things to correct I would like to suggest a major revision

Comments for author File: Comments.pdf

Author Response

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Reviewer 4 Report

I have read the manuscript thoroughly and found that the work has merit to be published in this journal. But it has some flaws that need to be resolved:

1. Please quantify the abstract.
2. Introduction should be updated by recent literature.
3. Data description is required along with path/row, spatial resolution.
4. Discussion part is missing, please it should be also updated by recent literature. More complex and seperate discussion would be needed. I would like to see more discussion here about the possible application of this method to other places of the world. What do the authors propose? Comparisons with other studies have to be provided in the discussion section
5. Conclusion lacks limitation of the study.
6. Please add future research direction in the conclusion

7. Keywords should not be the repetitions of the title words, please find such words which are not in the title, this way search engines of the web will find your manuscript with higher probability.

Minor issues

Table 1: What It Shows (Better remove)

Figure 8: legend is missing

Table 5: Cartographical errors such as legends, and text are difficult to read

Author Response

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Reviewer 5 Report

The manuscript "Uneven Development or not? Temporal-Spatial Variations in Chengdu Ranging from 2015 to 2019 Based on Remote Sensing Information", submitted to the journal Land, proposes a methodology with uses stratified the Support Vector Machine method to extract urban built-up area based on the Night-time stable Light, Normalized Difference Vegetation Index and nighttime Land Surface Temperature (LST) data to describe temporal and spatial variations of urbanized areas, by using the Chengdu area in China as a case study.

1. The main problem with this article is the way it is structured:
first (and major), after the results there is no real discussion on the results.  After Section 4, devoted to the results , the manuscript provides two very short sections (wrongly ordered, as the discussion should always come before the conclusions!) that fail to deliver what a good discussion and a good conclusion should do.  This, in turns, makes the article poor in terms of  clarifying why it is relevant and how/to what extent it is novel.

1.a) In the discussion, the authors should look at their result in the light of previous research, so that the reader can understand the significance and added values of their article: for instance, does this study confirm or contradict previous findings? and whose findings are they? This also entails that the discussion should clearly demonstrate what is the manuscript's added value and contribution to current knowledge, and, therefore, that the discussion MUST contain references to previous works that deal with the topic/the method (or parts thereof).

1.b) The conclusions should not only recap the major findings, as done in the manuscript, but also make a case for its novelty and potential usefulness  (for whom? and, for what?), for the replicability/exportability of the method (for instance, are there any conditions that might prevent its use elsewhere?), and the limitations, leading to the need for further research. The latter (limitations & further research) are the only part which is currently present in the manuscript.

2) Moreover, still on the structure of the manuscript, subsection 2.1 (Study Area) is ill-organized, as the second part (from line 99 to line 135) is not about the study area, but about data and their retrieval, and contains ill-described part. For instance, concerning table 1, in line 111 we read that "[...] equal to 500m spatial resolution. as shown in Table 1"; however, table 1 does not describe data characteristics, including the resolution, but only provides spatial and multitemporal representations of the three datasets.

3) Overall accuracy and kappa are introduced out of the blue in the results (line 204), without mentioning what they are and how they are calculated. A good article does not take for granted that the reader is familiar with them.

4) Also, although the intended meaning is generally conveyed, the language is riddled with errors. Many of them are quite annoying and could easily be avoided, such as the hyphen that incorrectly breaks several words. Maybe it comes from a glitch from some copy and past from another document with syllabation on.  Just to provide one example of such issue if we look at paragraph spanning from line 67 to line 74, we have "sur-face", "rang-ing", "extract-ed", "calcu-late". Furthermore,  some sentences really make no sense (see, for instance, "Whether uneven development has resulted?"), some words are systematically used incorrectly (e.g. "researches" does not exist, as "research" is uncountable), verb tenses are sometimes incorrect (for instance "The global Moran’s I index [...] always be employed [...]", "We resample the NPP-VIIRS NTL data [...]"). I spotted a lot of other errors, so I would warmly suggest that the authors have the article proofread by a language expert.

 

Author Response

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Round 2

Reviewer 1 Report

The authors have addressed all my concerns.

Author Response

Thanks very much for the valuable comments and suggestions, which help to improve the quality of this study greatly.

Reviewer 2 Report

The label in the middle of Figure 10 looks messy. It is hard to read them.

Author Response

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Reviewer 3 Report

Dear Authors,

Thanks for addressing the review comments and with this I would like to accept the manuscript in present form.

Author Response

Thanks very much for the valuable comments and suggestions, which help to improve the quality of this study greatly.

Reviewer 4 Report

All the raised comments were resolved. Accept in present form

Author Response

Thanks very much for the valuable comments and suggestions, which help to improve the quality of this study greatly.

Reviewer 5 Report

I am partly satidfied with how the authors handled the previous round of comments.

One comment, in my opinion, could betted be addressed and it concerns the discussion: very little effort has been made in putting the results from this study in the wider research context - only five references, all of which from Chinese studies. In other words, I would suggest that the authors better position the oucomes from the research by not only looking at Chinese case studies, but at the wider question addressed within this manuscript, i.e., how to effectively monitor uneven development by using readily available data rather than ad-hoc, long, expensive surveys.

Also, in equation 7 "GMI" should simply be "I" (the way the global Moran index is cited throughout the manuscript).

Finally, I do not think that the first part of the current, revised title ("Impact of power on to uneven development") works, as it does NOT convey the main idea in the manuscript, which is NOT that power affects/impacts on development (although this is mentioned both in the abstract and in the introduction), but, rather, that electric power (light) can be used to trace and explain development.

Author Response

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