I have a 32-bit GeoTIFF elevation file that was created using GPS survey points in Autodesk Civil 3D. It has been exported as a GeoTIFF with a custom Null Data value of -32767 for use in another program (GlobalMapper), which treats this value fine as a null value. When I bring it into ArcMap 10 (SP4), the lower value of the data is -32767 and shows up as a black collar around the area of interest (which is a fairly level area about 1010 - 1050 meters) making the area of interest solid white. The values in the black area are -32767.000000.
When I open the properties of the GeoTIFF in Arc, the NoData value is -3.40282346639e+038 in the Layer Properties -> Source -> Raster Information -> NoData Value block. I have tried to edit this value here (not editable) and in ArcCatalog by doing the same process (also not editable). Is there any way to set this value to -32767 so that it nulls out the black collar? I don't really want to change the NoData value in the data, just the NoData definition in the GeoTIFF's properties.
If you are just trying to change the display of the raster in ArcMap it is not necessary to alter the value for NoData. Simply add that value as the background value and then make it no color in the layer properties. The another way if you want to change it, would be to use the Copy Raster tool to create a new raster and then define the nodata value differently.
You can make it no color in the symbology, but how do you remove it from the statistics? Elevation grids are usually stretched, but when you have such an outlier that is included in the statistics you will usually just get black and white image.
Note that you can use the calculate statistics geoprocessing to to calc the stats and exclude a values such as -32767, however, if you like to use stretch using statistics from current extent (in order to see more detail) then you are out of luck as ArcGIS goes back to including those nodata (-32767) values again in the statistics. Very Frustrating.
You should set -32767 as the nodata value rather than leave it as background, which is a real pixel and is included when DRA is used. Using Set Raster Properties to define the nodata value is faster than using Copy Raster to do the same, since this tool doesn't have to copy the data.