Being a newbie at this, I should probably put my hat in the ring and show what I've obtained through my mapping efforts so far.
I had both played, and GM'ed, in Greg Stafford's Glorantha, featured in Chaosium's Runequest. But as great a world as that is, I was looking for something a bit less "fanciful", more "down to Earth" in certain respects.
Esrela is a world I conceived originally for Avalon Hill's Runequest III, as such it generally incorporates the same cultural and magical conventions. The sorcerous magic system playing something of a mythical role in its geological history, while such events still being plausibly tectonic in origin.
On the subject of geology, I am mostly a blank slate in the knowledge dept. here, but I've tried to think through a coherent idea of land mass formation. I beg the forbearance of those who know geology. Of course revisions are always a possibility so suggestions are welcome.
Below is an overall sketch of the world concept, showing only major landmass and mountain ranges inked, plate boundaries in pencil and volcanic points in red. Only the more permanent features with respect to geologic time. The quad scale is 500 miles wide, 250,000 square miles per quad.
My area of focus for the map is the clear western area of the southern continent, Ellos. The northern continent of Wespasia, being more politically unified, is not really quite as conducive to gung ho campaigning as the wilder, balkanized barbarian and nomadic cultures of western Ellos are. As a result, I have generally put my efforts there. I tend to neglect most areas that are not directly involved in campaigning.
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Ellos is formed on a broad east-west orogenic belt with a southern tectonic plate drifting north and subducting under its neighbor. It's southern coast hosting a portion of the resulting volcanic arc. Several strato-volcanoes are present along this area of the main continent, with several others out to sea. One of those, the round one off the west coast is a gargantuan shield-volcano. Think, Mars' Olympus Mons on that one. Hmmm, perhaps I'm leaning back toward the fanciful after all...
The vulcanism of this region plays into the myth of an ancient culture of advanced sorcerer-kings who engaged in experiments in extending their life spans unfortunately resulting in a proliferation of undead monstrosities; some of which still lurk about, against which the natural world rebelled. Something which a modern scientist could dismiss as coincidental to a natural tendency toward occasional, stupendous cataclysms. The inland sea near the center of the target area is the remnants of a massive, prehistoric caldera. Another smaller caldera occurs just east where the main mountain range group intersects. This smaller feature being the scar of the sorcerer smackdown. "LET'S GET READY TO RUMBLE!"
Though there are many gaping holes in the detail, I had hand drawn a fair amount of this region, decades ago, in 500 x 1000 mile sections on 1/4" quadrille ruled paper at a resolution of 25 miles per quad. These I scanned in, cropped and fitted, using this as a background layer from which to flesh out the landmass and ocean. I tweaked GIMP's grid system to match the paper grid fairly close enough to serve as a placement guide. I also have a semi transparent copy layer of the handmap to overlay for working in details. I'm confident that I can get my computer generated features placed to within several miles of the originals. Less than an hour's walking time for a healthy PC.
I employed a combination of Oldguy's realistic shoreline procedure, producing the rest of the image below from RobA's tutorial and palate colors. I wish to thank both of them for this guidance. I can't really call it my first attempt as I made a lot of blunders before it came out this good. In the process learning the delete layer command quite well...
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The original file is 3073 x 3250 pixels which is roughly a pixel per kilometer. From this I can produce local detail and city maps as needed. Now to try to figure out mountains and calderas...as always, suggestions are welcome and appreciated. Hope you enjoy this work in progress. (I assume that is what WIP stands for.)