I am not sure what exactly is causing hiccups for me - how I processed the data (removing the white edges in 3rd party software), the bit depth (8bit), the file format (png to support transparency), the number of bands (4 for the alpha) or something I am not thinking off.

This is what I want, although it can't be 2 layers. Both images in Arc

This is the closest I have come to combining them properly. This is a Mosaic operator of First image added. Mosaic to New Raster, First image added logic.

I thought this would work since the transparent pixels have values of 255 255 255 0, however the Mosaic Operator of Minimum was way off. Mosaic to New Raster, Min image logic

Then I thought - why the heck not and did a Maximum operator as well. Mosaic to New Raster, Max image logic

All of these are not usable to me. Can someone please help me understand how to get pixels to not overwrite legitimate data with NoData values while mosaicing? Also I could use any pointers to information about how to remove the collars around imagery like this.

Limitations --- I cannot use the Display Background Value because that removes white from the background of the maps too. I also can't use Mosaic Dataset functionality (oh how I wish!) because of licensing limitations.

1 Answer 1


Well sadly I just had to work around it. I mosaiced them in a 3rd party image editing program and brought them back into Arcmap and geo-referenced them on top of the originals.

  • Have you done anything like this since? I am doing the same thing now and having trouble.
    – sparky
    Commented Feb 25, 2020 at 17:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.