Before we even start we are going to talk a bit about how to use geography to make interesting gameplay. A map made up of entirely land isn't going to be very fun. Shape is one of the main things that can change gameplay, and you most often use water to get shape. You want to have a good amount of water in order to make some places harder to attack and other easier. Using peninsulas and bays along with flat coastline is what makes interesting maps. You don't want too much of the map to be water or else you will get very few territories (you could try to make the water into territories, but that doesn't always work.)
Here is the image I am going to start with:
Here we go!
[spoiler=Basic Land]So, I made the outline with the pencil tool, one pixel circle. When you first make the outline, it will look really jerky, but it is okay. Draw the outline of the land, then use the bucket tool to fill it in with black. YOu end up with this:
You want to make sure to duplicate that layer.
Next, make a new layer, called "water". Find a nice shade of blue, not too light, not too dark, and fill the whole layer with it. I am not sure if you need to, but duplicate this layer too.
Then, select the layer of black and white land. Using your color select tool, select all the black.
Make a new layer, above the water layer. Using the bucket fill, fill in the area you should still have selected with some sort of lightish green.
Now you have your basic land and water.[/spoiler]
[spoiler=Land Color]Now, no one wants to play on a map that is purely green and blue. A two color pallet it not what we are going for. I am going to show you how to make it look kinda like land.
Make a new layer, entitled "land color" or something like that.
Next, with the pencil tool, just make lots of blotches of color. Use things that make sense; yellows and tans for beaches, light green in some areas for fields, dark green for forest, etc. You are going to just make it really rough, just sorta color like you are a little kid who doesn't know how to color in the lines. You are going to end up blurring it, which means that it is going to become more transparent near the edges, so extend the colors out, so they go out over the water.
Here is what mine looked like once I did this:
Duplicate this layer, trust me, you don't want to start over, and your about to mess it up beyond fixing. Make the duplicate not visible.
Merge the land color layer together with one of your land layers (remember, you should have duplicates of both).
Then go to:
Filters >> Blur >> Gausian Blur. Set the blur to something pretty high. I used 60px by 60px. Make sure it is blurred enough that the colors blend well and look natural, but not too much, so you still have some difference.
Also, you can do the exact same thing with the water. I won't show you that, cause it is the exact same thing.[/spoiler]
[spoiler=Texture]Now, this land looks 'aight, but we can do better. No land is just a solid color, or even a blend of solid color, there is always more noise, and texture. We are going to add a bit of both.
With your land layer open, go to:
Filters >> Noise >> RGB noise. This will be used to add random Reds Greens and Blues. A dialog box will come up. Make all the values about 4 or five. If you are doing it for the water, you might want it a bit higher.
Then, go back to either your old black and white layer, or your land layer that has not bin blurred or changed at all (Remember how you were supposed to be duplicating things!) and select the white or whatever isn't the land. Go back to your land layer (the one with texture) and hit delete. This will trim it back so it doesn't overlap onto the water. Then, duplicate this layer again, but don't make the duplicate invisible. This will make the color a little richer along the coast, where it might have shrunk back when you blurred it.
Now, you are going to make a new layer, call it texture or something. You are going to go to:
Filters >> Render >> Clouds >> Plasma. A box will come up, with a slider thing a preview box, and a button or two. Look at the preview, you want one that doesn't have any spots that are really dark. Hit new seed a lot until you find a good one. Then hit render, I think and it will make a nice texture. It will be pretty satureated though, so you are going to go to colors >> desaturate. I honestly don't know what any of the other options it gives you means, but whatever sort of desaturation you do, it should work. WARNING!! On some versions of GIMP running on Vista, GIMP may crash here. If this is happening, let me know, I will show you a way around it, but I didn't want to have to put that up here. Below is what your texture will look like.
Select the texture layer, and go to blend mode, (it is on your layers box thing at the top, if people really can't find it I will show it) then set the blend mode to multiply.
Change the opacity to about 40 or 50%.
Did anyone notice that midway through I took away an island?[/spoiler]
[spoiler=Mountains and River]Now, you are going to need to add something to make the gameplay more interesting: impassables.
We will start with a mountain.
First, make a new layer called "Mountain." Put it above everything else. On this layer, using a pencil tool, you are going to make the base of the mountain. Get two shades of brown, one dark and another even darker. Draw a big smudge with the lighter one, and then on half of it, draw over with the darker one, so it looks like this:
Then, you are going to use the gaussian blur again, about 40-60 pixels each way. Add the same amount of RGB noise to this layer as you did to your land. Then, duplicate it, keeping both visible.
Now, make 2 new layers. Call one "snow" and the other "mountain effect". On the layer called snow, using the airbrush tool on a small brush size, draw some bits of white on the top of the mointan range, as seen below. They represent how mountain peaks would look from above.
Next, on your mountain affect layer, you are going to make it look more like a mountian. Using the airbrush tool, at 40% opacity and a very small brush, make a lot of short lines going out from where the snow is, for the darker side only. On the lighter side, change the opacity of the brush to about 30%, and make the same sort of strokes out.
For a river, you will just use a blue color, similar to whatever you use in your water. In a new layer with a very small brush, one or two pixels in diamiter, draw the first half of your river, comming in from the sea. Then switch to a smaller brush, and check the box that says "fade out". Set the number of pixels for the fading to match how much river you have left. Then, starting from where you stoped the first half of your river, draw the rest.
Next, you are going to go to:
Filters >> Lighting and shadows >> dropshadow. As seen below, make the x and y offset zero, and the blur radius 2.
Now you have a mountain, and a river!
[/spoiler]To add territories, use the brush tool, one pixel circle. Go to brush dynamics (below your layers) and set the spacing to 200. Then in a new layer draw your borders. Then set the opacity of the layer with borders down to like 70%
Finally, for bonuses, just use the airbrush tool. A nine pixel fuzzy circle should work. Go along the inside of the region you want to be a bonus (in a new layer). Then, in a new layer from that, probably below the one you have the territory borders in, trace the territory borders along the outside of the bonus regions with a very small fuzzy circle brush at about 30% opacity.
Congrats, you now have a nice looking map, ready for use!
Note: Parts of this tutorial have been borrowed from this: http://www.jezelf.co.uk/tutorials_map04.htm
