I have two GTOP030 DEM images. After downloading them, I have imported into ERDAS and mosaiced them. Then I have exported it to .tif file in order to open it in ARCGIS. But when I tried to open it in ARCGIS, "the memory could not be 'read'" error message appeared on the screan and turned off ARCGIS. what's wrong with this. Do you have any idea for this? Another thing I ask from you is how to remove No data value from this DEM file because min value of this DEM image is -9999.