Slope Grid With Reduced Resolution

[LornaMurison]

Hi everyone,
I have two grids that I need to line up perfectly with the same resolution.  One is slope and one is soil depth.  The soil depth one I have projected with a cell size of 100m (original was GCS NAD 83 0.005 deg. resolution at roughly 45 deg. latitude) with a registration point of 0, 0.  The DEM has a resolution of 10 metres.  I can create a slope grid from this DEM specifying an output cell size of 100 metres, but I don't know at what point, and how, the resampling is done.  Is the DEM resampled to 100 metres and the slope calculated from that, or is the slope calculated from the 10 metre grid and then resampled to 100?  And which resampling technique is used (bilinear, cubic)?
If I use the resample tool to resample the DEM (so I can specify bilinear) it gives me an error message saying the output cell size may be too large or too small.
Finally, the output slope grid that I was able to create does not line up exactly with the soil depth grid.  The project raster tool allowed me to enter a registration point, but is there another tool that will allow me to shift the raster grids without re-projecting?
Thanks!

[CarrieDavis · Accepted solution]

Hi,

I would suggest resampling your raster before running the Slope tool in order to have the option to chose 'Bilinear'. This option will be available in the environment settings in version 10.1, but is not available in prior versions. When resampling the projected raster as bilinear you may set the soil raster as the "Snap Raster" in the Environment settings of the Resample tool.

Snap Raster (online doc. about this setting in environments)
http://help.arcgis.com/en/arcgisdesk...0000000m000000

Only issue with this is that you will need to run the tool with background processing unenabled due to a bug that is corrected in 10.1, but not yet in version 10.

NIM061506: Snap Raster does not work correctly with background processing enabled.
http://support.esri.com/en/bugs/nimb...1/TklNMDYxNTA2

You may turn off background processing in ArcMap under Geoprocessing Options.

Hope this helps.

Carrie D.  Raster Support Analyst