Terrain Development Guide

Chapter 3: Optional Terrain Development

Rivers

A river network is very much like a road network (Part 1), except we place river textures instead of road textures. The only difference with rivers networks is that wide rivers or lakes require an additional step. An example of a river network map is shown below.

For narrow rivers that are smaller than a grid square, the procedure is exactly the same as with roads. The river map uses palette indices to determine which river texture gets placed at any given point on the map. For example, color index 1 might point to a river running east-to-west, while color index 2 might indicate a river starting in the west, and curving northwards; etc. The same technique of transparency textures is used for these rivers. Below shows the combination of a river texture with transparency and a base ecology texture:

If a river/lake is wide enough to cover multiple grid squares then we must generate a set of river-front textures and place them as appropriate. An example of a river/lake-front texture is shown below.

Because of all the combinations of rivers, river/lake edges, and transitions between rivers and lakes, you will most likely find the largest number of textures supporting a river network layer.