Remove "excess" after applying kriging interpolation

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10-18-2012 04:36 AM
EmmaGale
New Contributor
Apologies if this is not the correct place, or if this has been answered before, but I am new to ArcGIS so struggling a bit.

I have points with precipitation values, and I have applied kriging from the interpolation tools so that I have an interpolated precipitation surface for Thailand.

However, this has been done to a rectangle about the same size as Thailand, so includes areas that are ocean/other countries that I am not interested in.

Is there a way to only display the interpolation within Thailand?

I have (hopefully attached the example of the current map I have). I want to have everything inside the black line depicting the border or Thailand.

Thanks in advance! (Also, I am very new to all of this, and teaching myself, so please explain things in a very basic step-by-step way).
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4 Replies
MarcinGasior
Regular Contributor
To produce surface only in country boundaries you have to set Environment Settings.

Click Environments... button on the botton of tool dialog.
In Processing Extent section select "Same as layer 'Boundaries'" where 'Boundaries' is layer with country boundary.
In Raster Analysis section select 'Boundaries' layer.

This should ensure that output raster is nicely clipped to boundaries.

Moreover, you may look at article Interpolating Surfaces in ArcGIS Spatial Analyst to read about other interpolation methods (as kriging is not always best option).
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EmmaGale
New Contributor
Thanks!

That kinda works, except for the fact the layer I have for my country borders is a worldwide one, so it only snaps to the continent border. Do you know how to just extract the Thailand shape out of that layer (I could really do with a layer that is just the outline of Thailand but haven't be able to find one and I don't know how to make it myself)?
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EricRice
Esri Regular Contributor
Greetings,

The Kriging tool from Spatial Analyst honors the Mask setting in the environments.  So, you can set the country of Thailand for the Mask, rather than using it for Processing Extent.  The Processing Extent will still produce a square result that doesn't comform to a nations border (an irregular shape).

Environment Settings > Raster Analysis > Mask

Since you have a worldwide dataset for countries, you can just select Thailand, then right click the layer in the TOC, and choose Data > Export Data - Export just the selected record.  Use this new layer for the mask.

What version are you using?

Note, if you don't want to redo the Kriging because it possibly takes a long time to complete, you can just take the result you have, and the newly created Thailand layer, and run Extract by Mask.

Best,
Eric
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EmmaGale
New Contributor
Since you have a worldwide dataset for countries, you can just select Thailand, then right click the layer in the TOC, and choose Data > Export Data - Export just the selected record.  Use this new layer for the mask.

What version are you using?


I tried doing this, and I keep getting an "Error saving object" message. My ArcGIS can be funny sometimes, and works if I close and reopen, so I will try that.

I think I am using version 10.
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