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Weird checker-pattern after Raster Re-projection & calculator

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01-05-2023 10:33 AM
MemphWatershedAssoc
by
New Contributor
‎01-05-2023 10:33 AM

I took a LiDAR DEM and re-projected it from VT State Plane Meters to US ft. Then I converted the elevation attributes from meters to feet by multiplying by 3.28....

When I compare the Meters raster to the US ft raster, there is a weird pattern visible. The first screenshot has a bit of a checker-board pattern. The second (original), looks a lot smoother.

MemphWatershedAssoc_0-1672943465153.png

 

MemphWatershedAssoc_1-1672943481929.png
 

Is this an issue, or more of a graphical thing? The pixel size is the same for both (0.7m from the original DEM), but I'm not sure how that might have changed when I re-projected it. Should I have re-sampled and changed the pixel size?


lastly, If I'm merging this raster with topo-bathymetry data (TIN to raster), do the pixel sizes need to all be the same? Do I need to set the TIN to raster pixel size at 0.7?

Thanks!

 

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1 Reply
Luke_Pinner
by MVP Regular Contributor
MVP Regular Contributor
‎01-05-2023 01:45 PM

Did you leave the "Resampling Technique" as the default "Nearest neighbor":

The Nearest option, which performs a nearest neighbor assignment, is the fastest of the four interpolation methods. It is primarily used for categorical data, such as a land-use classification, because it will not change the pixel values. It should not be used for continuous data, such as elevation surfaces.

Use Bilinear instead.