Optimal Sampling Intensity in South Korea for a Land-Use Change Matrix Using Point Sampling

Round 1

Reviewer 1 Report

I have no further comment.

Reviewer 2 Report

Thanks for the comments and corrections you made to the text. I think these corrections have improved the quality of the paper.

Reviewer 3 Report

The comments from the review were taken into account and the reviewer's doubts were resolved. The article may be published in the "Land" journal. The content of the article is consistent with its title. The article is interesting.

In this article, the primary objective of the research was to measure changes in the state of land use in specific periods of time. The authors' research goal was to determine the optimal sampling intensity in terms of satisfactory statistical indicators. Final indications of sampling intensity were determined taking into account statistical accuracy, statistical efficiency, economic efficiency and convenience. In the opinion of the reviewer, the authors achieved the intended research goals.

Comments for author File: Comments.docx

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.

Round 1

Reviewer 1 Report

Understanding the characteristics and trends of national or regional land use changes is of great significance to formulating relevant land management policies. The article uses the optimal sampling intensity to construct a land use matrix in South Korea, in an attempt to provide a reference for formulating a national greenhouse gas inventory. The starting point of the research is meaningful, but the content does not have much innovation. Although the abstract, introduction, and conclusion have repeatedly emphasized that "sampling" can serve the climate system and reduce, the main research content is not clearly related to the research background and significance. And the research content is not sufficiently attractive regardless of the research background. Summarilly, it is recommended to switch to other regional publications. 
1) The abstract part should make clear the research significance. 
2) The introduction does not explain the academic value of this study in terms of land use theory, methods, and policies. The research review has no strong logical connection with L92 "South Korea should calculate...". It is recommended to supplement the national strategic needs, current research gaps, and the academic contribution of this research content, instead of just imitating existing literature and changing a research area to continue to apply research ideas. 
3) After reading the full text, there is no strong correlation between the research topic and greenhouse gas emissions. It is necessary to improve the presentation level of the introduction and strengthen the description of scientific value and innovation. 
4) Section 2.1, the sampling intensity is the core content of the article, but it is too simple to determine by only one sentence of description. It is recommended that the author supplement the details of the sampling intensity determination, and supplement the conceptual definition of the sampling intensity in this article. 
5) There is one point that I don't understand personally. The current world remote sensing technology has already surpassed the basic stage, and the relevant large-scale land use interpretation methods are very complete. Since there are already national aerial photographs data, why not directly analyze the country's land use changes. 
6) What is the Kappa coefficient of the national aerial photo interpretation dataset? Is the accuracy guaranteed? 
7) The scientific nature of the process of estimating historical land use spatial data based on the linear interpolation method of sampling points remains to be studied. At present, there are many researches on the theme of historical land use reconstruction in the world, including HYDE, SAGE and other data sets can be used. 
8) Section 3.1 is not suitable for the results analysis and can be adjusted to the materials and methods. 
9) The conclusion part should briefly describe the key results. The current writing style is more like a discussion. 

Reviewer 2 Report

The article "Optimal Sampling Intensity in South Korea for a Land-Use Change Matrix Using Point Sampling" presents an interesting issue related to land use change using point sampling. Study present optimal sampling intensity for measuring systematic land-use changes, and with analyses showed that a sampling intensity of 4 × 4 km was the most ideal fit.

The title was formulated correctly and closely refers to the content of the article. The content of the article is readable, and correctly divided. Paper is well structure. The background and bibliography are well defined.

My suggestions and comments are mainly related to materials and methods part and part of the paper with results.

Firstly, I think that in materials part, information about used data should be written more clearly, especially part about aerial photographs.

Also, I think that authors must provide more explanation, how justified is the use of linear extrapolation, given that deviating from known values can cause significant deviations – line 167.

Line 226-229 I think that is mistake 78,350 ha, and that it must be 48,350 ha.

In figure 2, uncertainty of each land-use category by sampling intensity is presented, but we can see results from table 4, and results for 2x4, 4x6, 6x8 and 8x8 is not presented in the text. Please explain.

After implementing these minor revisions, as far as I am concerned, the article can be accepted.

Reviewer 3 Report

Comments for the review

The content of the article is consistent with its title. The article is interesting. The authors studied changes in the land use sector in terms of assessing climate change. Forest land was selected as the land particularly influencing the indicated changes.

In this article, the primary objective of the research was to measure changes in the state of land use in specific periods of time. The authors' research goal was to determine the optimal sampling intensity in terms of satisfactory statistical indicators. Final indications of sampling intensity were determined taking into account statistical accuracy, statistical efficiency, economic efficiency and convenience.

In the opinion of the reviewer, the authors achieved the intended research goals.

There are possible minor mistakes related to the English language, to be corrected at the stage of final editing of the text.