What does the DEM Detail parameter mean?
The DEM extraction is hierarchical. That means that it makes several correlation passes, starting at coarse resolution overview images, and working its way up the image pyramid. Setting the DEM Detail allows you to stop the correlation process at some point in the pyramid, so that you are using less detailed imagery for the correlation. For coarse data such as SPOT or RADARSAT, you would usually leave the detail at High. However, for high res imagery such as photos or IKONOS, the imagery will include features that you don’t want in the DEM, such as individual trees, cars, people, sign posts, towers, etc. Often, the detail is set to Medium or Low. This stops the correlation at a reduced resolution image, which often no longer includes small artifacts like this due to resampling. So, think about the types of features that you want to show up in your DEM. If you want the tiny high-res features, set Detail to high. If you want a more general, smoother DEM, set the detail to Low.
