[R-sig-Geo] gstat: Variogram with non-Euclidean Distances

[Julia Dechamps]

Dear list,

I am wondering whether there is a way to use a contiguity-, graph- or knn-based measure of distance (similar the neighbourhood objects described in "Applied Spatial Data Analysis with R, ch.9.2.2-9.2.4), rather than Euclidean distance, to construct a variogram (in gstat or otherwise). 

The observations I have are very unevenly spaced across a large geographic area and I therefore feel Euclidean distance might not be a good choice.

I have searched the web but unfortunately was not able to find any hints on how I might implement the above.

I would greatly appreciate any advice you might have. 

Regards,
Julia