Assessment of Empirical Algorithms for Shallow Water Bathymetry Using Multi-Spectral Imagery of Pearl River Delta Coast, China

Round 1

Reviewer 1 Report

The paper presents a concrete application of prediction algorithms for determining the water depth from satellite imagery data, for the Pearl River Delta coast in China. The paper applies 4 different analysis methods, to both Landsat 8 and Sentinel-2 images, with and without previous data clustering. The results are interpreted, and several discussions are carried out. 

The paper is clear and well written, the analyses are relevant and appropriately carried out. The results are clearly discussed.

Perhaps a more detailed description of the filtered data and features used would contribute to a better understanding of the analyses made. Though the data is described textually, perhaps a tabular, quantitative description of the size of the datasets, and exact features used for both Landsat 8 and Sentinel-2 images would be relevant - for all the different analyses performed.
- Table 2 and Figure 5 captions should be written in absolute terms, i.e. not as "Same as ..."

Author Response

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Reviewer 2 Report

I find the problem very well described. The methodology is clearly exposed and the results are interesting. By the way,

a) how did the Authors manage to take into account the effects of the tide mentioned in section 2.1?

b) Would it be possible to use the same scale in all graphs in figure 7? And,

c) In the same figure, could a measure of the error  be added in the estimated depth?

Finally, 

d) what is intended exactly by "The tidal propagates from offshore towards the estuary with a mean tidal between 0.3 and 6.5 m, due to excavation activities", in sect. 2.1. ?

The manuscript would benefit from a general review of the significant digits, especially in order for the depth values to be consistent with the statistical error obtained.

Author Response

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Reviewer 3 Report

The reviewed article approaches the assessment of empirical algorithms for shallow water bathymetry using multi-spectral imagery. In this article it is analyzed a case-study from China.

The abstract is well structured and includes relevant information. However, in the abstract were identified some acronyms without explanations. Please provide the necessary extended name (see RMSE(MAE)). Please also mention which is the main conclusion of this article (in this form is not clear).

Overall the article is very well written and structured. There are no major shortcomings in this work, the methodology is well selected and applied and the results are correctly presented.

However, the conclusions section can be extended, in this form being considerable underdeveloped. Please explain also the scientific value of your article, how the results can be used given the challenges identified in the introduction section.

Also please improve the quality of figure 7.

I recommend a minor revision.

Author Response

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