Prediction of Water Content in Subgrade Soil in Road Construction Using Hyperspectral Information Obtained through UAV
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript is well-written and well-organized. The introduction effectively contextualizes the importance of moisture management in roadworks and highlights the limitations of current methods. The technical details related to image acquisition, database preparation, atmospheric correction, and modeling procedures are clearly articulated. The discussions on influential factors and algorithm performance are insightful.
To enhance clarity and rigor, the following aspects could be improved:
1) Provide a more detailed explanation of site conditions and the physical/moisture retention properties of the investigated soil.
2) Include spectral/chemical characterization of key materials.
3) Clarify sensor/sampling specifications, coordinate systems, and describe the workflow/tools used for pre-processing.
4) Discuss the assumptions, constraints, and uncertainties in the modeling approach, and assess the sensitivity and robustness of the model.
5) Substantiate the claim regarding the application of CCM through demonstration/validation on new data.
6) Analyze the implications and provide guidelines for linking CCMs with construction management practices.
7) Recommend long-term monitoring strategies to establish predictive capabilities.
Author Response
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Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authorsapplsci-2851013-review
Prediction of Water Contents on Subgrade Soil in Road Construction using Hyperspectral Information obtained through UAV
In this study, CCM (Color Coded Map) was proposed through hyperspectral remote sensing using drones. This method is a range-type water content measurement method that can acquire data in a short time and can be easily confirmed visually. This is an interesting and valuable topic. I think this is a very scientific and rigorous paper. We have obtained some valuable results with certain innovation and applicability. Therefore, I suggest accepting it directly.
Comments on the Quality of English LanguageMinor editing of English language required
Author Response
We appreciate your review.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsFigure 18b.. missing caption for this part of figure
The spectral curves in the 400 to 1000 nanometer wavelengths are quite smooth and do not have any narrow absorption bands (Figure 1. I wonder if the same results can be achieved with a multispectral camera, with bands chosen to characterize the curve, and a band at 0.93 ,microns to capture the relatively broad water absorption band. This would make the technique available to a much wider group of engineers who may not have the resources to use a hyperspectral camera.
How easy is it for a non-computer specialist to use MLR to analyze these data? Again I am thinking of how to distribute this method to non-specialists. Your technique is believable. What is not apparent is what is the next step to make it practical.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsA very interesting and novel paper was presented.
The following points need to be addressed before publication.
The abstract is good but to improve add a clear and distinct aim for the study.
The reviewer comes from a pharmaceutical analysis background and so the limits of detection and quantification may be interesting data to be presented in the abstract. This would show the lowest possible water content that can be discovered and be measured confidently respectively. If this is not an accepted method of presenting the data in the civil engineering world please provide an equivalent.
The journal is applied science, so therefore there would be a varied range of readers. Thus it may be useful in the first paragraph of the introduction to give some data for typical water contents of soil and civil engineering materials.
Very good argument is made for the need of the study.
In the introduction more information is required in terms of how reflectance with wavelengths measured in 4 nm increments is related to water content. Difficult to understand how hyperspectral information leads to a water content determination. The data acquisition process is clearly labelled but the underpinning mechanism is required. For pharmaceutical materials, water content can be related to absorption bands in the near infrared spectral range. Infrared radiation is passed through the material, and at a wavelength of 1950 nm water in the material absorbs the radiation and this is measured relative to the intensity of the incident light and absorption value is therefore calculated. Something similar is required for the mechanism which is the basis of the water determination here. The basis of the technique becomes a little clearer when the atmospheric correction is discussed, but the reflectance spectrum in the UV/Vis range 400-1000 nanometres needs to be described. What would a purely water spectrum look like in comparison to a completely dry soil sample?
Section 3.1.1, it would be interesting to know how flat the determination area has to be in order for the study to be applicable.
Line 191 to 192 it will be useful to know the weight of the extra equipment.
Please include the temperature and humidity during the experiments and soil sampling. The performance of the camera may depend on humidity and most definitely the water content of the soil samples will be dependent both on temperature and humidity.
For the other and drying analysis is there evidence there wasn't significant mass loss from an empty cup. As they look to be made out of paper or plastic in figure 7.
Figures 12 and 14 could be placed in an appendix, as this looks like raw data in large spreadsheets or the program used.
It would be useful to have a delineated methods and materials section describing the approaches used followed by results.
A conclusion is required at the end of the paper. Along with recommendations.
Comments on the Quality of English Language
Good, just the odd typo.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
