I am trying to mosaic 3 data sets, 2 of which are bathymetry and 1 elevation data sets. The bathy data overlap the elevation data where it has NoData and the elevation data overlap the bathy data where there is NoData.

My problem is I keep getting NoData from 1 or the other dataset obscuring the actual data. This normally occurs after I Build Overviews. Creating footprints also does not work, ArcCatalog just tends to crash.

I have already created mosaics of the individual data sets and then try to mosaic using these. I have simplified my elevation data set and removed al the little islands and small NoData areas within the data set.

See attached picture.enter image description here

1 Answer 1


With large overlaps, I would suggest that you create a single layer using map Algebra. In your map algebra tool, you can decide which data is to be used in priority, e.g.

Con(IsNull("elevation"), Con(IsNull("Bathy1"), "Bathy2","Bathy1"),"elevation")

In this case, use one of the bathymetric rasters if elevation is null (=NoData)

Note: Make sure that you define the output extent as the max of all extents in the tool environment.

  • Thank you. I managed to order by attribute which worked this time. But I will definitely try the map algebra next time, this problem took me 2 days to get right. Oct 3, 2017 at 13:01
  • You are welcome. Feel free to add an answer to your own post with your solution, for the benefit of the community.
    – radouxju
    Oct 3, 2017 at 13:04

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