topic Erase a polygon from a raster in ArcGIS Spatial Analyst Questions

Erase a polygon from a raster

MarcusGriswold — Sat, 16 Oct 2010 14:55:55 GMT

Hi

I am attempting to erase a series of polygons from a raster set. I have ArcView w/Spatial Analyst version 10.0.

I have converted the polygon to a raster and tried to subtract the two and have tried this code to no avail.
SetNull( Not IsNull( [PolyRaster] ), [MyRaster] )

Any help would be appreciated.

Thanks

Marcus

Re: Erase a polygon from a raster

DanPatterson_Retired — Sat, 16 Oct 2010 22:11:30 GMT

request that you General post be moved here...do not duplicate post, it isn't good for seaches

Re: Erase a polygon from a raster

MarcusGriswold — Sun, 17 Oct 2010 00:14:09 GMT

Dan,

I am using ArcMap 10. The error I received was a parsing syntax error. Maybe we can start with square one if you have time. I have a raster and I want to erase the area of all polygons in a single shapefile from it.

Re: Erase a polygon from a raster

MarcusGriswold — Thu, 21 Oct 2010 18:12:08 GMT

This is the error I received from that code:

Messages
Executing: RasterCalculator SetNull( Not(IsNull( "protect" )), "nlcdforse" ) C:\temp\privfor
Start Time: Thu Oct 21 15:08:06 2010
SetNull( Not(IsNull( Raster(r"protect") )), Raster(r"nlcdforse") )
ERROR 000539: Error running expression: rcexec() <type 'exceptions.NameError'>: name 'Not' is not defined
Failed to execute (RasterCalculator).
Failed at Thu Oct 21 15:08:06 2010 (Elapsed Time: 0.00 seconds)

Any thoughts?

Thanks

Marcus

Re: Erase a polygon from a raster

DanPatterson_Retired — Fri, 22 Oct 2010 17:56:53 GMT

I can confirm that Not =! ~ the latter is used by 10 and note that there is no pop-up help or tool-tips to indicate so, so use ~ in place of Not and bookmark the page Bill referenced

Re: Erase a polygon from a raster

MarcusGriswold — Sun, 24 Oct 2010 22:53:56 GMT

Great - Thanks! It would be great if there were a better error associated with it.

Re: Erase a polygon from a raster

toddsams — Tue, 07 Dec 2010 13:57:52 GMT

Can this be done in SOMA tool? I tried and it gave a message that "Not" is not a valid operator (also tried ~). I am using 9.3.1

Re: Erase a polygon from a raster

RafaelFernandes2 — Tue, 14 May 2013 12:59:18 GMT

So I needed to do something like that, in 10. But in the result I get a raster without the erased parts, witch is good, but it also cuts other parts in my case, it cuts the top in a straight horizontal line, and the right side also in a vertical straight line.

Any suggestions?