I took over a database someone else had migrated to our system a couple years ago. The (SDE) database is not often used and is really just here for reference purposes. I went to look at some raster data today and it is in a raster catalog, which I have never used before. When I add it to ArcMap, it appears as one giant polygon, like so:
When I open the attribute table, I can see 26 rasters are contained in the catalog, but if I zoom in, no imagery appears, it remains the same block as above, no real "wireframe" either. I am wondering how rasters are stored in raster catalogs, is there usually a GDB or something that is storing the actual source rasters and the catalog is referencing that GDB? I'm thinking because the SDE database doesn't contain these source rasters anywhere, maybe that's why I can't view them via the catalog? Again, I have zero idea how raster catalogs work and the documentation doesn't explain their inner workings very well...
Portion of attribute table for reference:
When I first added the catalog to the map, there was a dialogue about it not being spatially referenced (coordinate system: <undefined>). I put a projection on it, but nothing changed aside from the warning dialogue going away. Not sure if I did something wrong by doing that or not.
EDIT: After some more tooling around, I'm wondering if maybe I can't view the rasters because I don't have the associated files that would create a legend. For instance, if the rasters were TIF files, you'd have associated .tif.vat.dbf files to create a legend. I can see the raster is there, just can't view it in the dataframe:
When one is selected:
Converting it to a mosaic doesn't seem to do much besides generate the wireframes: