Askath: Continents

[woodb3kmaster]

Hi again, folks! After all the work I did on my Zasháve map, and the 3D model I used it on (see that map's Finished Map thread for more info), I decided to map the rest of the planet Zasháve is on, Askath. My first attempt at a whole-planet map left something to be desired, so I've decided to map each individual continent and combine these maps into a single world map. So far, I've made enough progress to show two WIP continent maps:

ahsam_wip01.jpg matlas_wip01.jpg

One significant problem that has arisen has to do with changing map projections. While I drew the original world map in equirectangular for use in Blender, I reprojected each individual continent to a conformal projection (stereographic or Lambert conformal conic, depending on the continent's shape and size) in G.Projector to minimize shape distortion. This step was especially important in preparing my basic maps for refinement in Wilbur. However, reprojecting the finished maps back to equirectangular has been harder to get right than I expected. I've been using ReprojectImage to reverse my original projections, but even with all the parameters I used to generate my projections written down, reproducing the original equirectangular maps has been a matter of trial and error - mostly error. I have yet to succeed at getting my reprojected continents to exactly match their original shapes, which, as you might expect, gets kind of frustrating at times. Any advice on how to solve this issue would be very welcome.

A related question has to do with adding bits of Zasháve to the areas of the new maps where they belong, in the same projection as the rest of the map. I can reproject my existing equirectangular version of the continent easily enough, but the limited size of map outputs from ReprojectImage means that reprojecting the finished version of Zasháve would result in a massive loss of detail and quality. A version of ReprojectImage which can output maps larger than 4096x2048 would be ideal, as I could then use my full-size map with minimal loss of quality. However, any new version of that program would have to be able to save maps up to 16,384px wide to meet my needs, and I'm not sure how feasible that would be with its existing code base. If there are any other options that would do what I'm looking for, I'm all ears.

Well, that was a lot of reading. Kudos to you if you read through all of that text. C&C on anything is welcome, even if it isn't what I rambled on about. Thanks for stopping by!

[zhar2]

Love the topography, what did you use?

[Mouse]

Oh my! These really are very beautiful maps.

Sorry I can't be more helpful than just to add my note of appreciation and a little rep

[Azélor]

(Some people are more knowledgeable than me, so correct me if I'm wrong)

You are correct. While it is very easy to change the projection if the default one is equirectangular, retroprojecting to equirectangular is based not on mathematics but purely on approximations. Thus I would recommend to change the projection only after all the important modifications are made since it's very hard to go back.

I use mainly Gprojector to change map projection. Using that software, it is possible to only project a partial section on the map (I don't know it that is also possible with ReprojectImage). So if I want only the missing part of the continent, I crop the image to take only that portion and indicate the coordinate while loading the image. That circumvent the problem of having a file that is too large to handle. BTW, Grojector also has similar limits to the initial file dimensions. 5000px x 5000px is close to the maximum my computer could handle with the software.

[woodb3kmaster]

Love the topography, what did you use?

Thank you! I use Wilbur for all my topography. In particular, I'm following Wilbur-maker waldronate's tutorial here for this series of maps - first making three masks at final resolution, starting at a much smaller resolution in Wilbur, and doing successive terrain processing each time I double the map's size. I've been quite pleased with the results, although I find I have to tweak my process in different ways to really be satisfied.

Oh my! These really are very beautiful maps.

Sorry I can't be more helpful than just to add my note of appreciation and a little rep

Thank you very much, Mouse! To respond to your rep comment, I think it would surprise you to learn that neither of those maps existed a week ago. Now that I have a basic workflow for maps in this style, it doesn't take long for me to run through all the steps. Processing the terrain is probably the most time-consuming part of the whole process.

(Some people are more knowledgeable than me, so correct me if I'm wrong)

You are correct. While it is very easy to change the projection if the default one is equirectangular, retroprojecting to equirectangular is based not on mathematics but purely on approximations. Thus I would recommend to change the projection only after all the important modifications are made since it's very hard to go back.

I use mainly Gprojector to change map projection. Using that software, it is possible to only project a partial section on the map (I don't know it that is also possible with ReprojectImage). So if I want only the missing part of the continent, I crop the image to take only that portion and indicate the coordinate while loading the image. That circumvent the problem of having a file that is too large to handle. BTW, Grojector also has similar limits to the initial file dimensions. 5000px x 5000px is close to the maximum my computer could handle with the software.

It strikes me as odd that retroprojecting a map should be impossible to do with math. At least some projections have what amount to inverse formulas, which convert Cartesian coordinates on the map to lat/long. Transforming the converted coordinates to equirectangular should be elementary after that. However, I suppose it depends on the mathematical complexity of the projection. Thanks for the feedback, though!

Well, this reply got delayed by several hours while I started a third continental map:

khalsim_wip01.jpg

Same methods, same looming issues with projection. Anyone else who has suggestions on how to solve those problems is welcome to share them. Any other C&C is also welcome.

[woodb3kmaster]

Another night, another continent gets mapped:

neshqaar_wip01.jpg

I'm now considering using QGIS to georeference my maps and assemble them into a full world map. However, this is one of many sides of GIS that I'm not very experienced in. I'd love to get some advice from the more GIS-oriented members here as to the best way to go about assembling my world map this way while introducing as little extra distortion as possible. I know there are tutorials out there on georeferencing raster data, and I tried it once with my heightmap of Zasháve, but I found that it introduced some unwanted distortion. It's likely that I wasn't following best practices or had unrealistic expectations, but given my lack of familiarity with GIS, anything's possible.

Comments, critiques, advice, rep?

[woodb3kmaster]

Here's another first-draft map, featuring the last of the major continents:

zappag_wip01.jpg

This one was more of a challenge than the others, simply because it's such a different continent. Finding the right colors to use, and figuring out how to make the best use of Wilbur's river map on a frozen landmass, took some time. However, I rather like how it turned out.

At this point, the only new maps left to make are of two yet-unnamed micro-continents. They'll be more of the usual fare, so they shouldn't take too long to make. Then comes the tedious work of naming everything...

Meanwhile, I still haven't experimented any further with using QGIS to properly reproject and combine my maps; I've been more focused on getting the maps ready for that phase. If anyone with GIS experience can offer any pointers on the best way to georeference raster data while minimizing errors, please share. As usual, all C&C is welcome.

[woodb3kmaster]

I decided it was more efficient to put both micro-continents on the same map, so here they are:

minors_wip01.jpg

This is the last of my first-run WIPs for this project. Now comes the tedious stuff...

Additionally, I think I figured out why ReprojectImage has been distorting my maps: it doesn't let the user set standard parallels for the projections that use them (including the one I used most for this project, Lambert conformal conic). It seems to assume the standard parallels are at typical locations, probably 30° and 60°, which my standard parallels aren't. It doesn't exactly help that the user can't flip the conic grid for maps in the Northern Hemisphere, which means having to turn maps in that hemisphere upside-down before and after reprojecting them. I hope these limitations will be addressed at some point, but until then, I'm still stuck on how to project my maps back to equirectangular without diving down the rabbit hole of GIS. I'm not against doing so if necessary, but if there's an easier solution, I'd love to know about it.

[Mouse]

Hey Woodb3kmaster

I'm hopeless at projection matters. I just stick with the projection I started with, or none at all (other than various different types of perspective). All I know is the joint map looks really great.

My enjoyment of your map, however (and I hope you don't mind me saying this), was a little distracted by the rather bold and straight style of the ocean names. Do you think they might look a little better if they followed similar rules to the style you have already used for the names of your two continents? By that I mean tone down the contrast between them and the ocean itself, and perhaps curve the words so that they look a little more like they are lying on the surface of the oceans they name? Maybe even curve them so that they appear to be at one with the lines of lat and long - which is not to say that they should be perfectly parallel with the grid itself, but only that they look like they lie on the same curved plane?

Its only a personal preference of mine - so please just ignore me if you don't agree

[woodb3kmaster]

Thanks, Mouse! I agree that a more subdued, curved style for the ocean labels would look better; in fact, I've applied such a style to my latest WIP map below. Is this what you had in mind?

It's been a while, hasn't it? After solving my projection issues from earlier (thanks to some pointers from johnvanvliet), I got distracted making all sorts of pretty pictures of the full planet from orbit, using a few different programs. It's only now that I've finally gotten around to turning my planet texture into a proper world map. I've done two versions so far, in different styles. The first is just the same satellite-type style I've been using for the continent maps:

askath-color-moll01.png

The second, meanwhile, is more of a basic atlas style, with only outlines of the landmasses:

askath-mollweide-wip02.png

I might try elaborating this style with contour lines (which would be easy enough to export from Wilbur) as part of a larger atlas project, similar to vorropohaiah's Atlas Elyden, but that's a decision I'll have to put off while I finish earning my M.A. I also have another map in the works, but I'll save that one for a new thread.

Your C&C is, as always, welcome.