Dear Dr. Rocchini:
Well, my first reaction is that R squared is not an appropriate measure for
correlated data. Secondly, such a large area may well have an underlying trend
which should be removed before kriging is attempted and lastly the number of
observations seems very small if that is the only data layer available.
Sincerely
Russell Barbour Ph.D.
Research Associate in Applied Mathematics
Vector Ecology Laboratory
Yale School of Medicine
60 College St. Rm 600
New Haven CT. 06520
TEL: 203 785 2394
FAX 203 785 3604
email: [EMAIL PROTECTED]
Quoting [EMAIL PROTECTED]:
I've made an interpolation by IDW, Spline and ordinary kriging and
a cross-validation for all methods.
When I make a regression between predicted and measured values I reach an R2
of 0.0109 (spline), 0.006 (kriging), 0.0006 (idw), namely very flat curves
(lines).
What could I do? I think I'm using a small number of input values (62) for
the area that I'm considering (4000 km2).
Thanks
Duccio Rocchini
Dr. Duccio Rocchini
Dpt.of Env. Sci.
University of Siena
www.rocchini.net
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