Biomass and Crop Height Estimation of Different Crops Using UAV-Based Lidar

Round 1

Reviewer 1 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors estimated height and fresh biomass of three crops using UAV-based LiDAR. The study seem interesting, but I have troubles in following the majority of it.

The authors want to test the influence of flight height and speed on height and biomass estimation of the three crops. The problem is that, in my opinion, they don’t have enough combinations of the considered flight variables to do that. For example, they only have one flight over 90 meter above the ground. I would suggest to just focus on results for different levels of point density. Data analysis are confusing. Is not clear how they use the Pareto score and the reference is not enough. They state that “This method chooses the best number of points based on two criteria, namely the highest correlation and lowest Root Mean Squared Error (RMSE) and selects only those combinations for which no better combination exists” but is not clear on what they calculate the error. The whole results and discussions section have no tables. The majority of discussion is based on images and is difficult to follow. I think tables would work much better in order to understand your findings. I would also suggest to change the naming convention used for the flights (e.g. F21, F23, etc) in something more readable (e.g. HighDensity, LowDensity etc)

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors. In my opinion, the paper is not well written.  More importantly, to introduce a new methodology (The goal of this study was to investigate the potential of UAV-LiDAR for high-throughpu phenotyping of different agricultural crops) not only variants of what you propose).  This would require to have some very clear objectives. In my  opinion, objectives are not clear, and the methodology and validation sections are not convincing ... and generally poorly illustrated. Therefore, for the  time being, I cannot recommend to publish your manuscript.

  

The methods section is weak. You need to clarify the  steps (add a methodology flowchart, etc.)

 

 I recommend to the authors studying in deep these procedures and learn more recent procedures devoted to UAV-Lidar.

 

 The paper is not clear and the conclusions are not well founded.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors have satisfactorily responded all my concerns in the revised manuscript.

Author Response

Thanks for the positive feedback

Reviewer 3 Report

Dear authors. In my opinion, the paper is not well written.  A suitable experimental design should be used (if possible comparing against some established method(s) not only variants of what you propose).  This would require to have some very clear objectives. In my  opinion, objectives are not clear, and the results and validation sections are not convincing ... and generally poorly illustrated. Therefore, for the  time being, I cannot recommend to publish your manuscript. 

 

Author Response

Based on the indicated suggestions by the reviewer, we have made some additional explanations in this rebuttal and some changes in the manuscript.

 

Dear authors. In my opinion, the paper is not well written. 

Reply: we are sorry that the improvements which we included after the first round of reviews have in your opinion not provided sufficient improvement of the manuscript.

We have reviewed the writing style of the complete manuscript.

 

A suitable experimental design should be used (if possible comparing against some established method(s) not only variants of what you propose).  

Reply: for the experimental design of this manuscript, the paper of Jimenez-Berni et al (2018) was used as starting point, and the proposed 3DPI method was evaluated for LiDAR-UAV acquired point-cloud data. In the discussion an extensive comparison is made with other studies which either used LiDAR or TLS based techniques, or UAV-optical approaches.

 

This would require to have some very clear objectives. In my opinion, objectives are not clear,

Reply: Based on the previous review and your recommendations, we have focussed the objectives and made them more specific with the focus on height and biomass retrieval from UAV-LiDAR. This is also specifically changed in the title.

 

and the results and validation sections are not convincing ... and generally poorly illustrated.

Reply: Based on the indications of the editor, we have removed some unclarities in the methods section as described in the reply to the editor. Based on your recommendation on the previous version, we have included a flowchart figure (figure 2) to provide an overview of the methodology, and a table (table 5) was added which provides an overview of the effects of the flight specification on the height and biomass estimation.