Okay, now that I've had some much needed sleep, I'm ready to continue. Of course, last night as I started this, I didn't even thing to offer the parameters I would be using for world generation so everyone could follow along directly. So, here they are;
Highest Peak : 22302 feet
Lowest Depth : -4885
Circumference : 25000 miles
Fractal Seed : 1923767461
Roughness : 0.54
Percent Sea : 70
Land Size : 2.67
Fractal Function : Wilbur Ridged Multifractal
Editing Size : Large
Projection : Equarectangular
That gave me the following results;
(see first image below since I can't seem to insert them inline in the post)
I'm not going to do any editing on this world, we can use it just as it is. All we need to do is find ourselves a nice island to work with in this tutorial. (Note : It doesn't have to be an island, but I'm going to use an island so that we can get a good elevation range). As it happens, there is a perfect island for the purposes of this tutorial located in the lower left quadrant;
(see second image below)
Now the fun begins.
Having zoomed in on the island, there are two things I am going to need at this point;
1) A grey-scale version of the island
2) A range for the area being viewed
Optionally, I can also pick up a colorized version of the island as well, but it isn't absolutely necessary to have that at this point. In any event, we'll need to load the TG-Greyscale.ltg coloring scheme at this point. And yes, there are going to be some very drastic changes on the screen.
Print Screen is my friend, and I use it a lot. In this case, I'm going to use it twice. Once to capture a colorized version of the island, and then, after loading the TG-Greyscale.ltg coloring scheme, once to capture a grey-scale version of the island. These, I am going to paste into my graphics editor as two layers in a single image.
The last thing we need is a range for the area being viewed. For that, all we need is View>>Map Info Window. The number that interests us here is the North/South Range. In this instance it is approximately 1690 miles (2726 kilometers). We need this for scaling purposes in Terragen.
Now, working with our captured images, we need to trim all the junk off of them and get a nice square version of the grey-scale image. This is where having the colorized version as an additional layer comes in handy since seeing the land masses in grey-scale can be difficult. The simple way to do this is with the Select Tool in your graphics editor. The important thing here is to make sure you get the full range of view from top to bottom, like so;
(see third image below)
Again, this has to do with the scaling in Terragen.
Once you've selected the area you want to work with, copy the grey-scale version of that area into a new image. This image should be perfectly square, if it isn't you'll have to try again. If you are following along with the tutorial directly, your results should look something like this;
(see fourth and fifth images below)
Now we need to prep our image for use in Terragen.
This is a fairly straight forward thing. We want our image size to be 513 by 513 pixels (the largest that an unregistered version of Terragen can work with). So we'll resize as necessary. Then we want to make the image true grey-scale. Most graphic editors these days have a one-click feature for that usually under the Color Menu Drop-down. And then we need to save the image as a .bmp file.
And now we're ready to start working in Terragen. To save time, you can copy the grey-scale image above and use it in Terragen.