[R-sig-Geo] cross-variograms and relationship strength

[Edzer Pebesma]

If you want to think "direct" correlation, you'd have to compare the
semivariance function values and cross variogram value at short lag
distances. If you consider the sills at a larger lag distance, it is
spatial cross correlation: how strongly is variable A at location x
related to variable B at location x+h? Zero cross semivariances indicate
zero spatial cross correlation, positive ones positive correlation and
then there's the Cauchy-Schwarz inequality at both boundaries.

On 09/20/2012 01:40 AM, Michael Hewson wrote:
> Please excuse this basic question - I'm a bit befuddled.
> 
> If I have two cross-variograms - both with the same two variables.
> Both sill at about the same range.
> One has a higher cross-semivariance value at that range.
> Does that mean it has a "stronger" relationship - in a correlation sense? Or does the greater value for cross-semivariance indicate more "variance" hence less strength? Or can one not make any judgement on relationship strength from the cross-semivariance sill?
> 
> Michael Hewson | PhD candidate
> Climate Research Group<http://www.gpem.uq.edu.au/crg> | Biophysical Remote Sensing Group<http://www.gpem.uq.edu.au/brg>
> The University of Queensland | Brisbane Q 4072 Australia
> +61(0)408379373 | m.hewson at uq.edu.au<mailto:m.hewson at uq.edu.au>
> [cid:image003.png at 01CD9713.FFFDD350]
> 
> 
> 
> 
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-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de