I have a file that is assigned a US Survey Foot State Plane Coordinate System. When try to bring in an IMG file, it comes in with the coordinates being read as meter values, applied to my US Survey Feet model. The northing and easting coordinates are 3.28083333333 times too big. However, the elevation values are correct for survey feet.
So I tried on the import, telling Data Acquisition that contrary to what it read as my model units, that the units were meters. With this approach, the DEM northing and eastings come in 0.304800609601 times to small. The elevation values appear very screwed up using his approach, where the Z high seems to be pretty close to correct if the file was in meters, but the Z low is so small, its using scientific notation to report it. This is not consistent with the Z low from the initial import.
I have found the only way to use the data is to bring it in using method one, save it to an InRoads DTM. Then to scale the DTM using the Feet to meters conversion for X & Y but no scaling for Z. Unfortunately, the DTM is sos big that more than 50% of the time, InRoads stops responding somewhere in this process. It has taken me more than two days to try an create the two DTM's I need to cover my project.