Re: correlations and coordinates

John Caron (
Mon, 11 Aug 1997 10:34:56 -0600

Harvey DAVIES wrote:
> On Thu, 7 Aug 1997, John Caron wrote:
> > I guess I don't understand what you mean by "coordinate system".
> I assume you refer to my comment on following from John Sheldon:
> > > >       Not applicable..."correlation" does not possess "coordinates" the
> > > >       way we think of them.  [rest deleted]
> My comment was:
> > > I just want to emphasise my agreement by pointing out that one could
> > > equally well be considering correlations between different variables at
> > > the same station.
> I was merely pointing out that the variable which identifies the variables
> being correlated (e.g. station, met. measurements) is essentially nominal in
> nature.  It could be a coordinate variable with a string value (e.g. station
> name, type of measurement (e.g. "annual precip.")).  I (perhaps wrongly) got
> the feeling that some people were trying to re-cast such essentially
> non-geographic cases into geographic frameworks by adding essentially
> irrelevant (as far as calculating correlations) geographic hooks in the form
> of lat/lon coordinate variables.

I agree that its easy to confuse spatial coordinates with more general
"abstract" coordinates. Thanks for pointing that out.

In some cases, geolocating points used in correlations will be useful
for calculating spatial coorelation scales, stc.