Once again, it’s been a good while since the latest update. With the elevation map, I decided to postpone work with the high res map of Central Eocidar, and instead expanded the area I'm working on to include all of C. Eocidar, since that makes for a more natural boundary in terms of drainage basins. I’ve also done some work on updating the tectonics as well as the coastlines of some continents, so I’ve been sort of working on three things.

As there’s been some interest in a more in-depth look at how to produce the elevation maps, I thought I’d post one technique I use that is a relatively quick way of creating a reasonably detailed height map. For this, I’m going to work on the large island east of Eocidar that keeps switching its name (at present it’s called Dealenos).
Cpt 01.PNG

For this technique, it’s crucial to have an established scale explaining what each RGB value corresponds to in terms of elevation. In my case, the scale goes in 25 m intervals (though now that I’m using Gimp 2.10 I could use a more detailed 16-bit scale, I’ve decided to stick to my old 8-bit scale for now).

  • 0 RGB: -150 m
    1 RGB: -125 m
    2 RGB: -100 m
    ...
    6 RBG: 0 m
    ...
    255 RGB: 6225 m

The basic idea is to generate clouds and then tailor them to represent specific elevations, which are then painted onto the map, starting from low elevation and moving upwards from there. So Filters->Render->Clouds->Plasma (or whatever method of generating random clouds you prefer) and create some clouds.
Cpt 02.PNG

Next up, desaturate the cloud (Colours->Desaturate->Desaturate) and scale them to represent the lowest elevation levels with Colours-Levels. Since I want this layer to correspond to elevations between 0 and 150 metres, I’ll set up the output to 6 RGB min and 12 RGB max.
Cpt 03.PNG

Then set the layer mode to Lighten Only and add a black layer mask (making the layer fully transparent). Pick a nice cloud brush or scatter brush (the exact settings and opacity are at your discretion) and start erasing the mask.
Cpt 04.PNG

Once you’re happy you can apply the layer mask and optionally add a “Land Mask” so you don’t end up painting over the ocean (which you probably don’t want to do).
Cpt 05.PNG

Then you can apply the land mask and merge your new layer down. Now might be a good time to check how the map looks like converted into coloured elevation:
Cpt 06.PNG

From this point onwards, it’s essentially rinse-and-repeat with progressively higher elevation levels. Remember that you can always re-generate layers as necessary (or modify them individually, if you create an actual layer stack instead of keeping everything merged into one layer, which is an alternative method), as well as manually paint and blur the elevations as necessary. I tend to mix the various techniques pretty freely. If you wanted to quickly create the elevations for a large area, you could work on an entire continent (or even a world) at the same time, and progressively add layer after layer with increasingly higher elevations to quickly create a reasonably good height map while still maintaining a much better level of control than if you were to simply generate some clouds and use those straight up as the de-facto elevation map.

Here’s my island after adding the next two layers (150 to 300 and 300 to 450 metres), as well as some manual modifications (blurring things together and so forth).
Cpt 07.PNG

And after yet another two layers (this time I increased the interval: 450 to 600 and 600 to 900), and of course further blurring and other minor modifications.
Cpt 08.PNG

(At about this point I realised I had my eraser tool set to use the “hard edge” setting . And here I was wondering why things seemed so jagged and required quite a bit of manual blurring. Whoopsie…)

And after the layers 900 to 1200 and 1200 to 1500:
Cpt 09.PNG

With the base topography more-or-less done I switched into manual modification with just smooth brush for the most part, lowering areas here and there, making the ridges of some mountain ranges sharper, lifting some areas up and so forth. This is what I ended up with (perhaps not quite final, but close).
Cpt 10.PNG

Hopefully this gave some insight and ideas if you’re struggling with creating your own fictional elevation maps. I figure I might as well use this post for something of an update on my progress with Aduhr as well.


So, here’s how the low-res map of Central Eocidar looks at present, with the western margins largely done. The red line denotes the northern boundary of the area I’m working on, bounded by the northern arm of the Trans-Eocidarian rift as well as the Neyhra Trough (an aulacogen).
C_Eo lowres.png

As a bit of a sneak peek into the updated tectonic model, here’s this region of Eocidar at c. 100 Mya, when Dealenos and the northern landmass of Neraduhr begin to diverge from Eocidar.
Initial Breakup.png

Some of the coastlines are still fairly WIP in the above (as I mentioned I’m reworking quite a few of them). Here’s how the situation looks like around 75 Mya, close to when the ridge between Dealenos and Eocidar becomes extinct.
Complete Breakup.png

So, that’s it for this update. There’s more to come in the hopefully not-so-far-away future. Feel free to ask any questions/provide feedback and have a mappy February!