topic Re: Convert integer raster grid to float grid using one specific column in VAT in ArcGIS Spatial Analyst Questions

Convert integer raster grid to float grid using one specific column in VAT

TungNg — Wed, 24 Oct 2012 03:58:23 GMT

I have a integer raster grid which has a value attribute table with these column: Rowid, VALUE, COUNT, AWC_100, AWC_150 ... I want to convert that grid to a float one using the column AWC_150 from the VAT in ArcGIS 10.0

Does anybody know how to do this? Thanks

Re: Convert integer raster grid to float grid using one specific column in VAT

JeffreySwain — Wed, 24 Oct 2012 11:40:07 GMT

With the Lookup tool, you can create a new raster based on a field within the raster. Then you could use the Float tool to turn the integer to a float. You will lose the attribute table, but will gain the float raster.

Re: Convert integer raster grid to float grid using one specific column in VAT

MarkBoucher — Wed, 24 Oct 2012 15:02:46 GMT

How about just using the raster calculator and the Float() function?

Re: Convert integer raster grid to float grid using one specific column in VAT

SteveLynch — Wed, 24 Oct 2012 16:10:23 GMT

if the field in the raster attribute table is integer then Lookup will create an integer raster and if the field is float then Lookup will create a float field.

i.e the type of the field dictates the output raster type

Steve

Re: Convert integer raster grid to float grid using one specific column in VAT

TungNg — Wed, 24 Oct 2012 17:48:08 GMT

Thank you very much for your inputs everyone. I tried the Lookup function but ArcGIS kept quiting unexpectedly. Have anyone encountered this before? My area is about 83,000 km2 (32,000 mi2) and grid cell size is 1 km. I'm using ArcGIS 10 SP 5 in Windows XP SP3

Re: Convert integer raster grid to float grid using one specific column in VAT

SteveLynch — Wed, 24 Oct 2012 19:14:59 GMT

That equates to a 288 x 288 columns x rows raster, which is small.
- What type of raster, Esri grid, img, tiff, etc.
- Is the join persisted?
- What happens when you throw it into CopyRaster or ExtractByMask?

Thanks
Steve

Re: Convert integer raster grid to float grid using one specific column in VAT

JeffreySwain — Thu, 25 Oct 2012 10:10:58 GMT

Have you evaluated all of the values in that column that you are using to create the new raster? Is there odd values within it? Missing Values? Or as Steve refers to is there a joined table to the raster?

Re: Convert integer raster grid to float grid using one specific column in VAT

TungNg — Fri, 26 Oct 2012 02:30:31 GMT

Thank you very much jbswain & Steve. The grid I'm using is FGDBR type without any table associated with it. Somehow I changed from GRID to FGDBR type after clipping from a big raster to my research area. Today, I try to use Lookup for GRID raster and everything is ok again. I have no ideas what went wrong. Anw thank you again for your help guys