World Construction Set (WCS) uses the term "ecosystem" to refer to the type of landcover that is applied to the terrain. One way to create ecosystems uses the Ecosystem Editor, making assignments based on elevation, slope and other WCS Rules of Nature. In this scene, all terrain is initially designated as grass or rock based on the local slope.

Overridding these designation are Ecosystem Effects. This second method uses vector polygons to place specific landcover types. In this scene, landcover polygons were digitized using an orthophoto base map. Separate ecosystem effects were developed for agricultural areas, old fields, wetlands and woods. Many parameters can be adjusted to improve the realism of ecosystems including: image types, density, edge effects and color. In addition, different understory ecosystems can create layers of vegetation.