ArcScan saved edit not working

Question

I was performing raster cleanup on an image. I output the cleanup session via Save As in the Raster Cleanup menu, and added that to my map document. Now, when I try to use the Eraser tool, the pixels will only disappear for as long as my mouse button is down. As soon as I let up, they reappear. Can anyone think of why this would be happening?

Thank you.

BrianKaplan · Answer

I found the problem.  ArcScan cleanup tools will only work with 8-bit tiff files.   So when you complete your georectification, be sure to change the No Data option by either turning it off or specifying a value at 255 or below.

For example, values range from 0-255 in an 8-bit raster. If a nodata value is introduced, the bit depth must increased to 16-bit to store the nodata value, which would be the 257th value. The pixel depth, or bit depth, determines the range of values that a particular raster file can store, which is based on the formula 2^n where n is the pixel depth. For example, an 8-bit raster can have 256 unique values, which range from 0 to 255...(http://support.esri.com/en/knowledgebase/techarticles/detail/28470)

Another option I explored was converting the 16-bit georectified raster to 8-bit raster by using the copy raster command which provides the ability to convert to a different pixel depth.  I tried this and when I specified 8-bit output, I got 16-bits.  Am I stupid or is this a bug!!!!

Thanks

Brian

BrianKaplan · Answer

I'm still trying to solve this problem.  What I learned today though is troubling.  I used photoshop to open the PDF, adjusted the image to black and white and saved it as a tif as a single band.  When I bring the TIF into ArcGIS and symbolize it as two classes, all the ArcScan tools edit the image properly.  If I take the TIF and export it to another TIF, the new TIF has the same problem as noted in my previous message.  This is disturbing because after I georectify the image using ArcGIS and create a new georectified image, it cannot be "cleaned" with all the ArcScan tools.  So, what is happening that ArcGIS is rendering a TIF it cannot function properly with???

BrianKaplan · Answer

I'm using 10.1 and I'm having the same problem.  I started out with a pdf which I saved as a tiff.  I georeferenced the 3 band tiff and rectified it to a TIFF  I added one of the 3 bands to ArcMap and exported it so I only have one band to edit.  The magic erase tool was working but seemed to stop and the eraser tool never worked on this tif.  It erases but it pops back.   Any body found what the problem is?

Thanks
Brian