Identification of the Characteristic Scale of Fine Ground Objects: A Case Study of the Core Observation Area in the Middle Reaches of the Heihe River Basin
Round 1
Reviewer 1 Report
Review on Article remotesensing-1032426
The manuscript appears well written and structured, the methods are clearly detailed and the findings are well described.
My main concern is, that the authors describe two methods that were already introduced before and compare them, without making clear what the real novelty of their study is. So, I think it would help the paper if they state more clearly throughout it (abstract, introduction, conclusions) what the novelty of their work and benefit for the readers /other researchers is.
Furthermore, there seem to be some problems with the layout, which I mentioned in my detailed points below.
List of points:
- Abstract: „for practical observations“: I think it would be good to state here a bit more clearer why (and when) it is important to use the method you introduce
- l. 50 and hereafter: “Li”: shouldn’t it be Li et al., and the citation directly after it. Plus, the citation at the end of the sentence, [19], refers to another paper. Please check that throughout the text
- l. 61,62: “Generally, researchers selected remote sensing data of a particular resolution based on previous studies” – don’t they select the data based on what resolution is available as well, and what resolution they need from the different sensors available?
- l. 118 pp.: I think it would be good to write a bit more clearly what the new aspects of your research are (compared to the already existing methods)
- l. 126: shouldn’t it read “Heihe River Basin” instead of “Heihe River”?
- l. 127: “the river flows” instead of “flows”
- l. 153: “NASA” instead of “NASE”
- Table 1: What is “unclassified”, the main class, – a mixture of several types?
- l. 182: there is a “)” too much, or a “(“ missing before
- l. 186 pp.: Is this really all the subscript to the equation or should it be in normal text
- l. 192: “topography” is mentioned twice
- l. 201 p: the difference in spectral response could also be due to a different overpass time of day (i.e. different sun angles)
- l. 205: put "Table 2" in new line
- l. 210: “SRF” instead of “SPF”
- l.216 p: the mathematical terms are above the line
- l. 230: abbreviation “WRC” was not introduced before
- Methods: I think it would be helpful if you would add a paragraph describing what your addition to these two methods is
- l. 312: you introduce C0 and C0+C, but not C
- l. 376 pp: could the peak at 17 m be due to the size of the single fields (as seen in Fig. 5), or what could be the reason for it?
- l. 425 pp: If I understand correctly, you say that the three forest types have very different results, so you show all of them, but that also the results of the mixed class are different, so you show only one result – it looks as if you come to two different conclusions starting from the same argument?
- l. 494: “with as” – remove one of the words
- l. 540: “relevant research” – add one or two citations
- l. 570: “Using the semivariance method to analyze the heterogeneity and obtain the scale can obtain better results with effort” – what do you mean by the “with effort”, that it needs more effort than the other method?
- l. 181 p.: do you have any suggestions on how this issue should be further studied, what would be beneficial?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors present a study that aims to identify the characteristic scale of several different objects in the study area of the Heihe river basin. The methods applied to seem appropriate to me, although note that I only feel confident assessing the spatial statistics aspect, and not the pre-processing of remote sensing data. I think that the aim of the manuscript could be made clearer, and perhaps an expansion of the sample size would be more illuminating (see comments below).
1. The results suggest that there need to be more samples for each of the types (with the exception of corn) in order to make generalizations. Particularly in the 3rd category of mixed vegetation and buildings.
2. The research gap that is being addressed should be made clearer and brought back into the conclusions - i.e. discussing how this work builds on what has already been done. At the moment, I'm not sure whether it is a comparison of the two methods or showing how the two methods vary depending on the sample used. More could also be made about the detection of multi-hierarchical structures of features, and their importance in the application of these methods.
3. Related: the expansion of the study site extent (research scope, here) seems to have effects on the results, but the reasons behind this is not discussed in detail - I recommend more discussion of this, which links to my point 2 above.
Specific comments:
L49: By largest image, do you mean "image with the coarsest spatial resolution"? If so, reword as such. Also, it's not entirely clear what is meant by "that can identify the smallest and distinguishable ground objects in the image". I think there needs to be some tightening up of the wording here as this is key to the rest of the paper, and needs to be fully understandable to someone who perhaps hasn't thought about characteristic spatial scale before.
L53-54: Again, be clearer what is meant by "The homogeneous phenomenon at a certain scale may become heterogeneous when it exceeds a certain scale". I think what you are saying is that "Processes may be homogeneous at coarse spatial resolutions, but when increasing to a finer spatial resolution display themselves as heterogeneous", or something to that effect.
L73: Change indexes to indices
L102-117: There is repetition in here - remove the second instance of this block of text
L121-123: Change so it is all in the present tense (e.g. were to are)
L439: Only results from the exponential model have been presented, so we can't necessarily see from what is presented that this is the best fit model.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
