The top shows the values I have been getting after the mosaic to new raster tool. below is the values I have been getting for each smaller slope chunk. The above is showing raster catalog to new raster which I also tried. both traster catalog to new raster and mosaic to new raster come out with these wrong figuresenter image description hereenter image description hereI have used a large number of Gtopo30 altitude tiles and used the mosaic tool to create a large DEM for my area of interest. I am trying to get a slope for said area but when running the slope (Spatial analyst) tool I have large gaps. I split the large DEM up into smaller chunks and successfully run the slope tool on each. I am now trying to mosaic them together into a single layer. I have tried mosaic to new raster but this is not showing the full area and also the values have changed. originally my slope would vary anywhere from 0 up to around 85 but after running the mosaic to new raster 7.xxx is the smallest value and it rises to over 2000. Can anyone tell me what I have done wrong or another way of putting the multiple slopes together into one.

  • Could you prove a screenshot of the settings you chose in Mosaic to New Raster?
    – blabbath
    Jul 4, 2018 at 14:40
  • I mean provide, not prove, sorry.
    – blabbath
    Jul 5, 2018 at 6:52
  • @blabbath Ive added screen shots above. Im trying to add a picture to show the output I am currently getting but Im having trouble at the minute. Jul 5, 2018 at 16:45

1 Answer 1


I would think your problem is in the chosen Pixel type.
Check the smallest and largest values in all your rasters - or just choose a Pixel typethat surely fits your range. Click the drop down menu and in the right field you can read which one is right for you.
On a slope raster 16-bit signed should be a wide enough range.

  • I have tried with the 16-bit signed pixel type and I am am still getting the incorrect values. Jul 9, 2018 at 14:24

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