Combine DEM rasters

Discussion created by recurvata on Jan 28, 2011
I have several DEMs for adjacent counties, one per county. The problem with displaying them is that the values are calculated individually for each county, so that the high part of one DEM, displayed as white, matches up with a low part of the adjacent county (black). This makes for a contrast between the counties which isn't actually there.
I'd like to based on the values in all DEMS, so that the transition between counties is equivalent, either through calculating individual DEMs based on all DEMs, or by combining them into one.
Is either approach correct, and if so, what would I do to accomplish this? If incorrect, what should I do? Thanks.