I was given is folder of .gbdtable files that I cannot seem to add to QGIS. Eventually I need these files in .asc or .bmp format, and am using QGIS to accomplish that. I've seen info on the web about .gbd files from ArcGIS Desktop, but the folder I have contains only .gbdtable, .gbdtablx, .atx, .spx, and so on. Do I need these input layers to be in a different format? I've been trying to add these as layers, but QGIS says it is invalid.