how to specify a clip layer for polygonal declustering

[AxelThomas]

Hi,
when using the geostatistical wizard to apply polygonal declustering I am not able to specify a clip layer. There is no possibility to specify a clip layer in the input data mask
and the Clip layer drop down list (Kriging step 3 of 7 of the wizard) only shows <none> with no option to load a clip layer.
Any hints how to specify a clip layer here?

Thanks,
Axel

[EricKrause]

The clip layer in polygon declustering must be a polygon feature layer.

Polygon declustering works by creating Thiessen polygons from the input points, and the bigger the Thiessen polygon, the more weight that point gets.  The problem is that points on the boundaries will often have Thiessen polygons that are way too big.  I've attached two graphics that show the Thiessen polygons of our tutorial data, one with clipping and one without.  It's clear that without clipping, the polygons near the border of California are given too much weight.  By clipping to the border of California, the weights will be much more reasonable.

[AxelThomas]

Eric,
thanks for your reply. The 'why' is clear, my questions was about the 'how'. On Kriging step 3 of 7 of the geostatistical wizard there is an option to select a clip layer which in my case shows only a <none> (see attached image).
Where do I select the clip layer that should show up in the clip layer option?

Thanks,
Axel

[SteveLynch]

Axel

The polygon feature class must be in your map document. I.e it must be in your Table of Contents.

Steve

[AxelThomas]

Steve,
thanks, that did the job.
One might consider to add a little note in the documentation - I did not find this self-explanatory.

Regards,
Axel