topic Re: translating from 9.3 Raster Calculator to 10.x (python) Raster Calculator tool in ArcGIS Spatial Analyst Questions

Need help translating from VB to Python.

AlexFlanagan — Sat, 12 Jan 2013 22:02:33 GMT

I'm currently completing the spatial analyst training but unfortunately it was made for 9.3, while I'm using 10.1.

While using the raster calculator I'm having trouble translating this to python.

Example is:
SetNull([Ownership] <> 200 OR [Soil] == 901, 1)

Re: Need help translating from VB to Python.

DavidPetrey1 — Tue, 15 Jan 2013 12:56:42 GMT

Try the following:

SetNull(("Ownership"<> 200) | ("Soil" == 901), 1)

The Vertical Bar represents OR now. And raster names are within quotation marks. And I always find putting logic in its own brackets helps as well.

David
simplyGIS. Making GIS simple.
www.simplygis.co.uk/GISTraining.html

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Re: translating from 9.3 Raster Calculator to 10.x (python) Raster Calculator tool

curtvprice — Tue, 15 Jan 2013 15:55:39 GMT

the "not equal" operator in Python is "!="

The names in quotes are (technically) raster layer names.

Here's my shot at it:

SetNull(("Ownership" != 200) | ("Soil" == 901), 1)

Arc 10.1 help:
Comparing Map Algebra between ArcGIS 9.x and 10
Building Expressions in Raster Calculator

Re: Need help translating from VB to Python.

DavidPetrey1 — Wed, 16 Jan 2013 06:15:53 GMT

Ah yes, the new symbol for doesn't equal is !=, though I find <> still works (or is this just a random thing of my installation?), which I usually end up typing out of habit.

David

Re: Need help translating from VB to Python.

curtvprice — Wed, 16 Jan 2013 14:28:08 GMT

Ah yes, the new symbol for doesn't equal is !=, though I find <> still works

Learned something, thank you.

[noparse][/noparse]his is an obsolete usage kept for backwards compatibility only. New code should always use !=.

Python docs: Built-in Types - Comparisons