controlling feature class extent

CyndyBresloff — Thu, 30 May 2013 17:16:19 GMT

Hello,

I have a feature class, that I call into a Python script, that I then convert to a raster, and perform a conditional statement with, with another raster. The input feature class - and the derived raster from it - has a different, smaller, extent than the other raster I perform the conditional with. Within the conditional statement, the feature class derived raster is part of the conditional statement; ie: basically I say 'where the feature class derived raster is null, use the other raster's value; else, use the feature class raster value". The output result is of the extent of the feature class raster, and I need the extent to be of the other raster that is input in the statement.

Let me make that easier to follow 🙂

statement:

outCon = Con( IsNull(Raster("OutRaster")), Raster(gR), (Raster(gR) + 1.0))

OutRaster is the raster derived from the feature class. gR is a random raster.

I need outCon to have the extent of gR. I cannot seem to do this for love of chocolate! I tried to set the environment extent to what I need, but that appears to have no effect. How can I make this work?

Please let me know if I need to clarify my problem. Thanks!

Cyndy

Re: controlling feature class extent

RhettZufelt — Thu, 30 May 2013 21:41:36 GMT

Basically you are telling it to create a "copy" of the OutRaster file named outCon and changing the values in it depending on your where clause (looks at each cell of conditional raster and assigns a value based on clause). So, it will create a raster the same size/extent of the OutRaster as it evaluates all cells in the conditional raster layer.

To match the extent of the gR raster, you could try the arcpy.env.mask = gR setting before the con statement as SA tools are all supposed to honor masks: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001w0000001t000000

If you have problems with mask, another way would be to clip the OutRaster to the extend of the gR raster before the con statement.

R_

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controlling feature class extent

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