Problems with NoData in a large GeoTIFF

Discussion created by npssde on Sep 26, 2013

I'm looking for an explanation of this behavior in ArcGIS 10.1 SP1.  I have a large (~15Gb) GeoTIFF  raster with unsigned 16-bit pixel depth in which I needed to convert 0 values to NoData.  I used Raster Calculator with the SetNull command to do that, which works fine except the NoData value is now -2147483648 which promotes the bit depth to 32-bit signed.  This is really annoying because now the output raster is unnecessarily huge. 

How can I prevent this from happening? I've tried CopyRaster to set the bit-depth back to 16, but that re-introduces the 0 values in the NoData cells so I'm back where I started.  Any help appreciated!