[R-sig-Geo] corSpatial and zero distance

[valerio.bartolino at uniroma1.it]

Dear list,
it is probably a very simple question with an obvious answer, that unfortunately I cannot find by myself.

Why I cannot fit a spatial correlation structure model if I've some observations in the same location? Shouldn't the nugget account exactly for this small-scale variability and measurement errors?

I'm using one of the correlation models in the generic function 'lme' (package:nlme)

Thank you

Valerio

-- 
Valerio Bartolino, PhD

Institute of Marine Research - Swedish Board of Fisheries
PO Box 4, 45321 Lysekil, Sweden

Department of Earth Sciences - Gothenburg University
PO Box 460, 40530 Göteborg, Sweden

e-mail: valerio.bartolino at gvc.gu.se
        valerio.bartolino at gmail.com

><(((*> ----- ><(((*> ----- ><(((*> ----- ><(((*>