Parametric Modeling Method for 3D Symbols of Fold Structures
Round 1
Reviewer 1 Report
The paper proposes a method of producing 3D fold symbols via parametrically generated 3D models. The method has been shown to successfully construct several different types of geological symbols, representing, among others, anticline, syncline and recumbent folds.
While I generally find the article interesting, I have identified several issues which should be corrected before publication.
The introducing paragraph talks about 3D GIS and its evolution in "recent years", however some of the referenced papers are over 20 years old, and the most recent one is from 2015. This section should be updated to reflect more recent developments in 3D GIS, such as the various scientific applications of Cesium and the introduction and impact of the 3D Tiles standard. Moreover, introduction should also be expanded with a more thorough explanation of the applications of three-dimensional fold models.
The proposed fold modelling algorithm consists of many steps and involves sophisticated techniques such as creating and cropping bezier curves and vector morphing interpolation. It would be difficult to realize in practice without software-based aid. Has there been an attempt to implement such a tool? If so, what technologies / libraries have been used for this purpose?
The model coordinates given in Table 5 appear to be in carthesian space. Since the models represent particular geological structures, why not use a geographic coordinate system instead?
The constructed models are said to by stored in JSON, however Cesium currently does not provide a convenient way of importing custom models in this format. Could you elaborate on the process of importing your models into Cesium?
The subject of model complexity is vaguely mentioned in section 4.1, but it should be put into context. Please state what is the complexity (number of vertices / triangles) of the models used for the case studies, what hardware was used for the tests, and what was the performance when displaying the different models.
While the general fold modelling process has been explained in detail, texturing of the created models has only been given a brief mention in section 4.2. Yet, the model of Dayue mountain shown in Figures 13, 18 and 19 has clearly been textured. Please explain the reasoning behind the applied texture map: what characteristics it represents, has it been applied on the model as a whole, or separately over individual stratum boundaries, etc. Because the paper attempts to establish a new method of producing fold models, it should in my opinion either also define a standard texturing method, or avoid the texturing subject completely (in which case the indicated figures should be changed).
Detailed recommendations:
Section 2.3.1:
Did you mean "amplitude and wavelength"?
Figure 12:
There are minor errors in the depiction of the surface model (b). Firstly, the front section of the mesh contains a single untriangulated quad, and one of the triangles composing the top section of the mesh contains the back part of the middle arch, which should not be visible from this perspective.
Section 4.1:
Did you mean "the running efficiency tends to be lower when a model with a large amount of data is displayed in a complex scene" ?
Author Response
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Reviewer 2 Report
This is a very interesting work on parametric modeling related to 3D symbols for fold structure. In particular it is based on the usage of cross-sections generated by fold parameters and a contour comparison algorithm. The research is well conducted and the manuscript is appropriate. However, it requires some modifications and reviews. Please follow the list below:
- - Inside the abstract the following paragraph “the method involves….”: please remove the first bracket for each number and insert “:” after “involves”
- - GIS references shoud be extended to recent research on this topic;
- - A part from chapter dedicated to case studies, should be better to include a “results” section before the discussion chapter (on which I see some results).
- - Conclusion chapter can be enriched with more critical considerations
Thank you.
Author Response
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Reviewer 3 Report
This study proposes a parametric modeling method for 3D fold symbols according to the complexity and diversity of the fold structures. Generating a 3D geological symbol is represented by the process of constructing a 3D geological model, so that 3D geological symbols resemble 3D geological model.
The study is interesting and is significant for geological 3D visualisation. The paper is well structured and well written. The proposed method is well described, and the results are clearly presented through case studies. A few improvements are suggested.
Parametric modelling is well known in 3D CAD, however GIS users might not be so familiar with it, so providing some definition or explanation of parametric modelling in the introduction might be beneficial for the readers.
How is the proposed method implemented and what is the performance? Is there a possibility to visualise the attributes of the 3D fold symbol or to generate a symbol legend on a 3D globe? It may be useful to provide some more examples on a larger map.
Author Response
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Round 2
Reviewer 1 Report
The revised version of the paper has addressed most of my concerns, however there still remain some issues.
First of all, the authors state that they have added "introduction of test hardware" to chapter 3, however I have not found any mention of CPU, GPU or RAM specifications anywhere in the text. As long as the impact of model complexity on performance is mentioned (in section 4.1), a reference point for those assessments should be given in the form of hardware specifications of the test platform. Secondly, the expanded introduction section now contains several papers not written in English (references 8, 9 and 10, among others). While it is sometimes necessary to cite non-english literature, in this case it is possible to find alternatives which can be appreciated by the broad scientific community. If these issues are sorted out, I believe the paper could be fit for publication.
Author Response
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