Frequently Asked Questions R-WEL, Inc . The best computer for DMS is, generally speaking, the fastest one available with the biggest hard disk you can afford. A good system would have a 450Mhz or faster Pentium processor, accelerated video board with 16 Mb of VRAM, 128Mb RAM, and at least 12 GB of hard disk storage. Yes, you can. The original stereocorrelation algorithm developed for DMS was designed for use with SPOT stereo satellite images.
Several factors influence the final accuracy of correlated DEMs.
With good quality images heighting accuracy should be on the order of approximately 1-1.5 pixels. With moderate terrain, average images and a modern computer, you can expect to calculate about 100 - 400 elevation points per second. Working with images at this resolution, however, has its downside. Although you can see all of detail of the film, the file size is huge - a 2000 dpi scan of a standard aerial photograph results in a 324 Mb file. You need 2 of these to work in stereo and then a few derived files for the stereomodel and DEM - pretty soon you need about 1 Gb of free disk space per stereomodel.