topic Re: Arcgis 10 Raster Calculator Range in ArcGIS Spatial Analyst Questions

Arcgis 10 Raster Calculator Range

DeviyaniGurung — Mon, 20 Jun 2011 17:23:10 GMT

Hello,

this is a very simple question, but for some reason the new syntax in the raster calculator in arcgis 10 is confusing me. I would just like to extract a range and export it into a new raster.

In 9.3.1, I just did 23<=[dem]<=25. This doesn't work in arc10, I tried doing ("dem"=>23) & ("dem"<=25) but I end of getting the entire raster.

any ideas?

thanks

Re: Arcgis 10 Raster Calculator Range

EricRice — Mon, 20 Jun 2011 20:03:23 GMT

Greetings,

In many cases you have to tell the software what to do if the statement is true. You can consider using a conditional statement in this case if you want the output raster to have the same values as the input, but just be a subset of the full data range. The statement below worked well for me.

output =Con(("Raster.tif" >= 500) & ("Raster.tif" <= 2000),"Raster.tif")

If you want the true statement to be 1 and false to be 0, and not worry about maintaining the real input values you can just use this:

output = ("Raster.tif" >= 500) & ("Raster.tif" <= 2000)

Regards,
Eric

Re: Arcgis 10 Raster Calculator Range

JaredHowland1 — Fri, 07 Sep 2012 15:51:47 GMT

So I am trying to do exactly as described in this thread. I need to extract a range of raster values being .2 or greater and less than .4.

I am using 10.1 and I am using your code. Here is the example, this is exaclty how I put it in raster calculator.
("Compare.tif" >= .2) & ("Compare.tif" <= 3.99) and I keep getting errors as shown in the attachement.

Please let me know what I'm doing wrong.

Thanks!

Jared

Re: Arcgis 10 Raster Calculator Range

DevlynRobson — Wed, 17 Oct 2012 12:26:50 GMT

Hi

I have been having a similar problem trying to select ranges between 157 and 203 in 10. I tried the combinations listed above either got an error message or all pixels selected. I was going for a 0/1 answer.

Finally got it by using the following:
("aspect" > 157) * ("aspect" < 203)

Definably not the same way I used to do this is version 9!

Good luck!

Re: Arcgis 10 Raster Calculator Range

KailaiZhang — Fri, 09 Nov 2012 21:11:36 GMT

Hi Jared,

Please check to see if you have any other version of python installed on the computer. By default, the site packages for 10.1 should be installed under C:\Python27\ArcGIS10.1\Lib\Site-packages, see if you have a site-packages folder directly under C:\Python27\lib or something like that and there is no numpy within it. That could cause ArcMap starts python directly from C:\Python27\lib, and it gives an error about no numpy module found.

Regards,
Kailai

Re: Arcgis 10 Raster Calculator Range

JaredHowland1 — Wed, 05 Dec 2012 17:42:41 GMT

Thanks all for you replies!

I am getting numpy errors.

I did check the file path that you mentioned and I found a "numpy" folder. C:\Python27\ArcGIS10.1\Lib\site-packages\numpy.

What was it I'm supposed to do with this folder?

Thanks,

Jared