TerraGear is a collection of tools for building scenery for the
FlightGear project.  Generally, the process is done in two steps:

  1. Preprocess the original raw data.  This chops up the data into
     the FG tiling scheme and saves it in a simple, intermediate
     format.

  2. Collect all the different pieces of intermediate data and
     assemble them into a 3d model of the terrain.

WWW: https://github.com/FlightGear/terragear