A Spherical Volume-Rendering Method of Ocean Scalar Data Based on Adaptive Ray Casting
Round 1
Reviewer 1 Report
This manuscript proposes a 3D visualization method of ocean scalar field based on the ray casting algorithm to deal with the accuracy and efficiency of volume rendering of the ocean scalar field in the virtual earth environment. The algorithm addresses three key points: a spherical proxy geometry determination based on the minimum bounding volume, the integration between the volume rendering results and seabed terrain, and the adaptive step sampling algorithm to balance the rendering efficiency and the visualization quality. All these issues would contribute to the ocean environmental visualization and analysis. Thus, this manuscript may be accepted before addressing the following minors.
1) The experiment data should be addressed in Section 4, not section 2.
2）Two experiment datasets covers different spatial regions，and they have different spatial resolutions, why select two not one kinds of datasets
3) Section 4 lacks of comparisons with existing methods, especially the quantitative analysis.
3)Some sentences are unclear, e.g. Line 82-83
4) The legends are missing in Figure 9-13; the reference in Line 437 is missing; the spatial resolution in table 2 is incomplete.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript proposes a new method for processing digital ocean data. The topic is worthy of research; however, a minor revision of the manuscript is needed. In the current state of the document, it is not in the format requested by the journal in some cases. The manuscript is well written, but it will need more scientific rigor. The manuscript has several minor comments/changes that need to be addressed before it can be considered for publication.
General comments
C1. The main concern is that the novelty of the research is not fully clear. If such novelty is not clearly highlighted, the risk is that the manuscript looks more a simple case study rather than a research paper.
C2. The introduction section is very complicated to understand, it is important to improve the syntax.
C3. What are the major contributions of this study? should be carefully mentioned in the discussion section.
C4. What are the advantages and disadvantages of this study?
C5. Authors could also emphasize particular strengths and limitations of the study for potential applications of their method in other regions. Add a section on strengths and limitations.
C6. There is a lack of a section on discussion, where a real comparisons to other researchers of your results?. It is necessary to carry out a thorough comparison, I recommend to include some relevant references, in order to improve the discussion on the novelty of your study, comparing to the others.
*The answer to these questions should be reflected in the manuscript.*
Specific comments
Line 103: Please provide website link, day, month and year of access.
Line 109: Please provide more details about "preprocessing".
Line 112-113: Do not need to be two tables, combine into one.
Line 114: Include a summary of "GEBCO-2022" in the table above.
Line 115-117: Please provide website link, day, month and year of access.
Line 120: What program was used for preprocessing?
Line 172-182: To ensure repeatability of the study, please provide in which software(s) this was developed, what functions were used, mention more details about the parameterization.
Line 269: What are the units of "Ray direction"?
Line 270: A period is missing at the end of the figure title.
Line 313-315: Why select China's Yellow Sea and the Bohai Sea as the study area?
Line 362: Change "The" to "the".
Line 368: Delete the arc of Figures 10a and b.
Line 348: Edit.
Line 428: Edit font style of "an".
Line 437: Delete "[]".
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
1.Review and revise the grammar, syntax, and vocabulary to ensure that the English is clear, concise, and accurate.
2. The discussion section should be added.
Author Response
Response to Reviewer 3 Comments
We appreciate your valuable comments. We have addressed them as follows and accordingly revised the manuscript, and all changes have been tracked in the revised manuscript.
Point 1: Review and revise the grammar, syntax, and vocabulary to ensure that the English is clear, concise, and accurate.
Response 1: We have reviewed and polished the the language and revise the manuscript in “revision” mode. We have made a careful examination of grammar, syntax and vocabulary to ensure fluency in English.
Point 2: The discussion section should be added.
Response 2: Accrounding to your comment, in line 571-602, we have added a discussion section in the manuscript. The advantages of the proposed method over the existing methods are discussed from the aspects of visualization effect and efficiency. Detailedly, In section 4.1, we discussed the visualization effect of our method. We compared our method with the method mentioned in reference [19] and [20], the experiment result proved that the method proposed in this paper has advantages in the three-dimensional visualization of nearshore ocean scalar field. Then, we compared the nonlinear color mapping method based on skewness attribute of data set with linear mapping method. Accrounding to Figure 11, the nonlinear color mapping method show its strength in visualizing the local details of the ocean scalar field. In section 4.2, we discussed the efficiency performance of our method. First, we have verified the performance of the proposed method by testing the frame rate of two experi-mental data sets in the interactive state. Besides, we added a experiment to test the performance of the adaptive step sampling algorithm with the equidistant sampling algorithm. Accrounding to the result in Figure 15, our method has obvious efficiency improvement with the increase of data layers.
