topic Re: Study area mask in ArcGIS Spatial Analyst Questions

Study area mask

DanielP — Thu, 15 Aug 2013 05:19:09 GMT

I'm trying to determine the WofE in an area, with Arc-SDM toolbox. My problem is that I'm stuck with my study area mask. How do I set up a mask?

Solve it!!

Re: Study area mask

MarkBoucher — Fri, 16 Aug 2013 15:39:53 GMT

You can limit the area the geoprocessing works on by changing the processing extents.
Menu: Geoprocessing>Environments>Processing Extents and select the layer that defines the area you want to process. This set a rectangular area that fits extents of the features in that layer. The Spatial Analyst tools will only do there work in this extent. There are times when I've experienced the results coming out not not covering my study area. It is often because the extent was defined by some process and was not reset to the extent you want. I use this command to reset the processing extent.

You can "clip" the raster you are working on.
I use Spatial Analyst Tools.tbx\Extraction\Extract by Mask. This lets you use a polygon as a mask to extract just a portion of a raster you want to analyze. You may need to set the extent as described above anyway.

Link to topic:http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Output_Extent/001w00000009000000/

Idea: It would be nice if ESRI created a way to view the processing extent graphically. Right now, I think one can only look at the coordinates in the Processing Extents dialogue box and maybe somewhere else. You'd have to be pretty experienced with your NSEW coordinates or Lat/Long to just look at that and know it is right. (I posted this idea on http://ideas.arcgis.com/)

Re: Study area mask

EricRice — Mon, 19 Aug 2013 22:32:31 GMT

Mark,

Not that the idea is bad, especially if someone manually types in the extent and wants to "view" it... but if someone is choosing a layer, then we already provide tools/visualization of extent depending on if it is a feature or a raster. For raster, just display NoData in addition to real values - that is the extent. For features, there is a tool called Minimum Bounding Geometry. Choose the Envelope option to get a polygon output that is the extent.

Best,
Eric

Re: Study area mask

MarkBoucher — Tue, 20 Aug 2013 00:04:48 GMT

Eric,

Understood. It is just that sometimes, when the geoprocessing is not working the way I thought it would, instead of resetting the processing extent and trying the process again, it would help to simply display the processing extent to understand better where I was when the processing didn't work. It would help in the iterative learning I end up doing. Also, I have had some functions in Arc Hydro change the extent without my wanting it to. Then, I'd run in to strange behaviors that I can only explain by blaming some function. This one I could not repeat on that project, but it happened on another one. It might be a handy debug tool also.

Re: Study area mask

EricRice — Tue, 20 Aug 2013 13:22:59 GMT

Thanks for the extra feedback, Mark. I can see how it would be useful.

Best,
Eric

Re: Study area mask

WillSchwenger — Mon, 28 Apr 2014 17:52:49 GMT

I'm having a similar problem. I have set the processing extents in my model but ARC-SDM Calculate Weights keeps returning the following error. Any suggestions on next steps to fix this problem?