Automatically switch raster resampling defaults according to data type

516
7
08-09-2017 03:49 PM
Status: Open
ThomasDilts
Occasional Contributor III

Improper use of the raster resampling environment settings can lead to problems with rasters.  If the default option NEAREST is selected for continuous data then it can result in artifacts that appear as horizontal and vertical striping. The striping is especially problematic for DEMs, hillshades, slope rasters, and flow direction rasters and can even affect watershed delineation. Often these problems can be hard to identify and deal with at a later date. I'd suggest that ArcGIS should be re-designed to be smart enough to detect the proper resampling technique. If the data are integer then NEAREST could be the default, but if the data are floating point then BILINEAR or CUBIC could be the default.

7 Comments
SteveLynch

Because many of the inputs in Spatial Analyst's Surface toolset use elevation data their behind the scenes resampling has been changed.

From the help of Aspect;

When the input raster needs to be resampled, the bilinear technique will be used. An example of when an input raster may be resampled is when the output coordinate system, extent, or cell size is different from that of the input.

ThomasDilts

Steve, This is great to hear.  Also, it is a good nudge to get me going in the direction of upgrading to Pro.

SteveLynch

Thomas

Not to steer you away from Pro :-), but this change was made to ArcGIS at 10.2.1

ThomasDilts

Good to know.  That means that I've already got it on some tools.

KoryKramer

tomdilts‌ Are there other specific tools where you see this smart resampling default not working?  If you could provide examples we could share those with the appropriate team. 

Thank you!

ThomasDilts

This is my list, but I think that it would be great if the user community could weigh in.

Fill - default to CUBIC or BILINEAR
All the tools in the Interpolation toolset - default to CUBIC or BILINEAR
Most of the tools in the Local and Neighborhood toolsets - should be based on the input (if one layer is floating point then the output should use CUBIC or BILINEAR)
Map Algebra/Raster Calculator -  should be based on the input (if one layer is floating point then the output should use CUBIC or BILINEAR)
All of the tools in the Math toolset -  should be based on the input (if one layer is floating point then the output should use CUBIC or BILINEAR)
All of the tools in the Multivariate - default to CUBIC or BILINEAR
Mosaic/Mosaic to New Raster - should be based on the input (if one layer is floating point then the output should use CUBIC or BILINEAR)
All the tools in the Density toolset - default to CUBIC or BILINEAR
All the tools in the Distance toolset - should be based on the input (if one layer is floating point then the output should use CUBIC or BILINEAR)

Flow direction, watershed - default to NEAREST

SteveLynch

The interpolation tools, for example, do not use any resampling method. You decide on your cell size and a prediction is made at the center of the cell and that value is assigned to the cell.

-Steve