Remove "excess" after applying kriging interpolation

Question

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).

Kriging example.png

EmmaGale · Answer

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.

EricRice · Answer

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

EmmaGale · Answer

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)?