What are the kinds of values that you see in ArcGIS? Is this an ADF raster, i.e. a folder of many files like "w000001.adf" etc. ?
This is a just a guess, so sorry if it's off-base - I don't know of any non-ESRI tool to get at these values. If this is an ADF raster I know that you won't be able to access the descriptive/categorical values you would use in Arc, you'll just get the underlying integer index. (BTW, this lookup type with an underlying integer mapped to a 'descriptive value' is like the factor type in R - does that sound like what you have?). The raster is read via the GDAL library, which does not provide the "categorical values" you assign in Arc. It's just a part of the format that hasn't been reverse engineered by the GDAL developers, but further, if your descriptive values are actually text then GDAL cannot represent them - only numeric types are supported, even though the rasters in R can have text/character types. Cheers, Mike. On Thu, Nov 11, 2010 at 11:35 AM, Tyler Dean Rudolph <tylerdeanrudo...@gmail.com> wrote: > I have a pretty simple code to extract cell values from a habitat map > (RasterLayer) based on xy coordinates. I recently updated habitat > information with a new raster image but for some reason now when I read in > the values it's as though they are no longer being interpreted as discrete > values, so instead of select, discrete classes I am getting new arbitrary > groupings that I didn't create. The input file is a standard > ArcGIS-configured GRID raster layer. The attribute table in ArcCatalogue > displays the data as expected, and I've ensured the raster has been classed > as containing discrete values prior to opening it in R. > > Perhaps something in the packages have changed since I ran this last? I'm > currently trying to assess in the raster documentation what kind of > additional arguments I might have at my disposal in order to clarify how I > want the data to be read.... > > Tyler > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsum...@gmail.com _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
