Problem Mosaic-ing USGS DEMs

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03-20-2021 09:50 AM
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Happytrails
New Contributor

I'm attempting to combine 5 1x1degree Wyoming DEMs from the USGS database.  Ultimately, I need to create a custom DEM for a southern rockies study area to use for my project.  My most successful attempt has been using the mosaic to new raster function, but the result has a blank area that shouldn't be there.  I'm pretty new to working with rasters, so I'm not sure where I'm going wrong. I did try out other mosaic operators (blend and mean) but using those made the blank areas larger. 

My attempt:

Happytrails_2-1616258844714.png

 

The original rasters:  

Happytrails_1-1616258793168.png

I would appreciate any guidance on either using this tool correctly or direction to the correct tool to use to merge the DEMs needed for my project.

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3 Replies
JayantaPoddar
MVP Esteemed Contributor

Try MAXIMUM as the mosaic method.

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JayJohnsonWashoeCounty
Regular Contributor

If the white band is being caused by one of the rasters having a band of NoData at its margin (presumably the raster in the NW), maybe before the mosaic operation you need to clip that raster to include only the portion that you need (i.e. get rid of the NoData).

Jay
Washoe County GIS
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Happytrails
New Contributor

Although I haven't discovered the cause of the white spaces in my mosaic, I did find a workaround.  I combined the two rasters that were being finicky (bottom left and upper right).  I then mosaic-ed that new dataset back to the dataset of 5 with the white spaces.  This new data set has all its data visible and is mosaic-ed correctly.