Map Projections Classification
Round 1
Reviewer 1 Report
The authors of the manuscript argue that the classification of map projections based on auxiliary (developable) surfaces is not valid and propose another classification approach to be used in map projection publications.
Τo a certain extent their argument is justified and a new classification should be considered. Besides the logic described, this is supported by the references cited in the manuscript.
We have to bear in mind though that the existing classification has its roots to the old times where projections were drawn through the utilization of geometrical methods (ruler and pen). On the other hand -and in order to conceptualize the process- the meaning of term implies the operation to "project" a region of the earth to a developable surface. Especially for laymen who are not in a position to fully understand cartographic terminology, the existing classification enables them to get a basic idea on what is meant by a projection and its main characteristics.
As the authors emphasize (lines 124-127) in reality “The reference globe and developable surfaces are conceptual aids that help illustrate the projection process, but they are not used to create projections today. Rather, the field of mathematics is utilized to create projections, and so it is important to understand some of the basic mathematical manipulations used to project the Earth onto a map." In this framework and based on the desirable projection characteristics, the users select the one that is suitable for the kind/purpose of their map from the list of available projections in their GIS or Cartographic system.
The authors document the approach proposed that results to a classification embracing a wide range of projections. In doing so they –correctly- refer to a number of publications on the topic BUT they make excessive reference to their own publications (a number of them with overlapping content) something that should be avoided and rectified.
Another point of concern is the definition of the pseudo-graticule and the mathematical model associated with it. There is a need for a more elaborate presentation of the pseudo-spherical coordinate system and the way it contributes to the classification of projections.
Concluding, I am not optimistic that there will be a change on the way projections are currently classified, but it is good to publish this paper that may trigger discussion on this issue.
Improvements to be made:
-
Figure 4. Graticule (black) and pseudo-graticule (blue) on a sphere: The two graticules cannot be distinguished due to the colors used. Consider using thin and thick lines with different colors respectively.
-
Figure 6. Classification of projections according to the shape of the pseudo-graticule. It is also the graticule in normal aspect projections (a) cylindrical: Another cylindrical projection e.g. Mercator or Miller should be used instead of Plate Carrée
-
Figure 7. Image of the graticule in the Mollweide (a) normal; (b) transverse; (c) oblique aspect : The images portrayed are not clearly visible
- See recommendations for authors
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I generally agree with the authors that classification of projections based on auxiliary surfaces may cause misconceptions. I still find important, however, to emphasize that for young children and for people without appropriate mathematical background – and according to my experiences a considerable part of Geography students also belongs to this group – the best way to introduce the concept of projections and especially projection aspects is through illustrating it with various perspective projections. Naturally, it is also important to emphasize, that only these few projections can produced by optical projection, and the majority of them are deduced by pure mathematics.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper provides, in chapter 1, some constructive criticism of explaining and classifying map projections via developable surfaces. Chapter 2, then, reminds use of classification criteria more suitable for the subject matter.
While chapter 2 provides a sound and well structured summery, the criticism of section 1 is presented in an imo much less convenient form:
- The authors start by claiming that “So far, many books and textbooks of general, thematic and even mathematical cartography have been published, as well as articles in journals, in which one of the classifications of map projections is based on auxiliary (developable) surfaces and projections.”
Given the far-reaching reproach, you should at least provide some references, for example some cartographic textbooks and recent articles, to demonstrate that your claims are still valid.
- Instead of providing detailed reference, you base your arguments on Wikipedia. Imo that’s not enough for an academic journal. Of course, you can use Wikipedia as an additional source but not as your key witness.
- You provide a large list of bullet point with arguments against “projections via developable surfaces”. While most arguments are documented, the list itself is repetitive an partly unstructured. I highly recommend summarizing point where possible and divide your arguments in subchapters.
For example, “The authors of the oldest known…” and “E.g. Mercator, in the 16th century …” are parts of the same argument (and this not the only example). So you could (1) summarize this arguments or (2) introduce subchapters to related arguments.
Finally, I feel that the colloquial language of part 1 differences from part 2 and makes it more obvious that you aren’t native speakers. Maybe you have someone else to edit this part?
Some of the URL provided have been accessed already several years ago – please update.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Summary Evaluation:
The paper presents the authors' refined and rectified insight into the classification of map projections. The reviewer finds this article especially useful not only for the cartographic community, which is professionally engaged in this, but for all those interested in studying the processes of creating maps.
The paper is of high interest, written transparently, and its presentation is technically correct. Some comments are made in the text of the manuscript in the attached PDF file.
The reviewer has some comments and questions for the authors, believing that their answers will help to improve the manuscript, which are as follow:
- The abstract is concise and informative. But, it should be stated in one sentence what is the main approach for a more realistic and accurate classification of map projections from a mathematical point of view.
- The literature review on the problem is almost well presented. It can be supplemented by older publications before the introduction of "modern" concepts for understanding multiple map projections based on developable surfaces.
- Some of the individual judgments of the authors marked by bullets (about 20) are related and can be combined; some of the comments are on separate publications of authors related to similar conceptual notions for the classification of map projections. In this way, other publications that remain outside the scope of the authors' analysis presented in this manuscript may be omitted.
The reviewer considers that the manuscript can be accepted for publication in the journal after minor corrections and additions.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Reviewer quote (1st round): "We have to bear in mind though that the existing classification has its roots to the old times where projections were drawn through the utilization of geometrical methods (ruler and pen)."
Authors response: We disagree with the Reviewer. The use of rulers and pens cannot be a sufficient reason for
the introduction of developable surfaces.
Reviewer response (2nd round): It is obvious that the authors misinterpreted my comment. I do not support the view that rulers and pens are a sufficient reason for the introduction of developable surfaces. What I mean is that in the old times it was something that helped people to conceptualize the various projections and to develop graphical methods to portray the graticule.
