Hi all,
So I've solved this problem (hooray)! It seems that there is an issue converting the new NLCD layers (dated 02-14-2011) from ERDAS Imagine (.img) files to ESRI Grids. The USGS (creators of the NLCD data) have provided this work around to do the conversion:
in ArcMap:
1. Add image (NLCD raster)
2. Zoom (or draw) area of interest
3. Export area of interest to GRID
a. Extent = Data Frame (Current)
b. Spatial Reference = Raster Dataset (Original)
c. Rename the file name and select a desired output file format (i.e. GRID)
d. Click Save
*Ignore "Failed to Save Raster Dataset"
e. click OK
in ArcCatalog:
4. Arc toolbox - Data Management Tools>Raster>Raster Properties>Build Raster Attribute Table
a. input grid file
b. check Overwright
c. run
5. Data Management Tools>Joins>Join Field
a. Input Dataset = grid file
b. Input join field = value
c. Join table = (source NLCD image)
d. Output join field = value
e. Join fields
d. check - Red, Green, Blue, Opacity, Land cover
f. run
While this work around does work, if you are using ArcGIS 9.3 as I am, you don't have the join field option in the toolbox, so I used python to do the last step (I can provide code on request).
Thanks to Richard Vandersnick who supplied the work around from the USGS.
Hope that helps!
Katie