New answers tagged spatial-statistics
In a spatial database like spatialite this is a straightforward query. Suppose you have the polygons as parcels and the point layer is zoological (and both are spatial tables in spatialite). I'll assume the parcels has a unique id called parcel_id and the species has species_id as well as species_name and entity. The query would be something like: SELECT ...
I don't think there is any limit (mathematically speaking) to the z-score. I've got results up to 100-200 in some occasions. Just google search images of the morans zscore results and you will see a lot of cases with scores greater than 40.
As pointed out by @cengel, the ppp function in spatstat package will take care of the work. Please check the following link for detailed information: http://www.inside-r.org/packages/cran/spatstat/docs/as.ppp
I don't know that either would be 'more correct'. I would probably lean toward random points, since any regular spacing might introduce bias based on the pattern. You do not want an equal number of points. See http://en.wikipedia.org/wiki/Modifiable_areal_unit_problem Three samples of a large variable polygon might fall on values the same as a uniform small ...
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