WIP - A serious attempt at mapping a fantasy world

[Silversweeper]

After spending several years lurking on the forums and working on different versions of a world map for a fantasy world that I never finished, I have decided that it is time to make a proper attempt instead of several half-hearted ones. This means starting with tectonics and a *very* rough land/sea map.

The map is roughly equirectangular, though I have cheated a bit at the poles (the map stretches from about 85° N to 85° S). The planet in question is roughly Earth-sized and I have decided to assume that it has more or less the same axial tilt, planetary albedo, orbital period, a same size moon, etc.

One of the attachments shows just the land/sea outline. Note that this is extremely rough at the moment and that most of the smaller islands will either be removed, be split into multiple islands, or become much smaller before the map is done.

Another attachment shows a very rough mountain range sketch. The green areas are where I *really* want mountains, while the yellow ones are areas where smaller ranges or no ranges will work for the world I am envisioning.

The third attachment shows a very rough tectonic map, which I have attempted to base on where the important mountain ranges are. The arrows indicate how I think the plates should move, based on my limited understanding of tectonics and where I drew the mountain ranges.

Things I would like feedback on:
- Does the tectonics make sense?
- Do the green mountain ranges make sense, based on the tectonics?
- Which of the yellow mountain ranges make sense?

Things I don't want feedback on at the moment:
- The shape of the coastlines, unless it is related to the tectonics.

[Pixie]

Well, you better be "serious" and ready for hard work. Even with some leverage for changing landform, creating a tectonic basis for an imaginary continent is not an easy task. It requires that you know your geology and that you invest time and energy, since there will be a lot of trial-and-error.

At first glance, here's a couple of advices:
- break that plate 2, its movement is highly unlikely on a sphere (never forget you are working on a sphere!)
- think of your plates as parts of continental land that is ALREADY moving for a long time, that includes leaving a "trail" of ocean behind, which is still part of the plate
- save low-res versions of your map, every time you make changes and apply them as a layover using google.earth, then navigate - I find that the easiest way to develop a spherical understanding of the map

Read these threads throughly, a year ago, quite a few of us were doing what you want to do now:
http://www.cartographersguild.com/sh...ad.php?t=27216
http://www.cartographersguild.com/sh...ad.php?t=27111
http://www.cartographersguild.com/sh...ad.php?t=27204
http://www.cartographersguild.com/sh...ad.php?t=25903

[Deadshade]

My principal comment would be - first thing you have to do is to go over to a sphere because a planet is a sphere.

Then one of the most important thing to know that ANY movement on the surface of a sphere is a movement of rotation around a fixed axis. The point where this axis intersects the planet's surface is called the Euler pole so if you define the Euler pole for each plate, you can easily have the velocity at each point (V = angular velocity x distance of the point to the rotation axis) and direction.
The thing is that because the movement is a rotation, once you project the velocity on a plane, you obtain velocities and directions varying with the distance to the rotation axis (e.g that means that the velocity "arrows for a given plate have neither a constant direction nor a constant magnitude).
One of the consequences is that large plates where the Euler pole is in the direction of the largest size of the plate will be ripped apart by the differential velocities (like what Pixie said about your N°2)
This is practically impossible to do when you start with a plane projection (like equirectangular).

Your north pole plates look more or less ok on a plane but don't look OK on a sphere.
Your plate 3 looks unlikely because it is hard to see why it wasn't already destroyed by 1 or 2 which have a much bigger momentum.
Also there is definitely a lack of subduction which is what happens at the contact of oceanic and continental plates.

Last but not least you should look at the links Pixie provided - trying to reconstruct plate tectonics for a fantasy planet is a recuring subject on these boards and these threads illustrate that it needs much patience and much work.