OpenEV Developer Course
A complete online course written by Vexcel Canada (formerly Atlantis Scientific) for it's own developers. It includes a three part tutorial, major components, files, extending OpenEV, scripting, building and maintenance.
OpenEV Library Design
OpenEV Library Design. Also available in PDF (500KB).
Source Code Documentation
GDAL Design
OpenEV does all raster file access using the GDAL library. File read/write access is achieved through Shapelib (directly built into OpenEV) for ESRI Shapefiles and optional read access for additional formats can be achieved through OGR (OpenGIS Simple Features Library) which is distributed as a component of the GDAL .dll/.so.
As well, OpenEV uses the OGRSpatialReference and OGRCoordinateTransformation objects for projection and coordinate system related services. These are also from the GDAL .dll/.so. The underlying reprojection is actually achived by PROJ.4, which is dynamically loaded by the OGRCoordinateTransformation if available when reprojection is requested.
Thanks to Ben Discoe of vterrain.org for generating this diagram.