Paulo van Breugel schreef:
Dear all,
I am exploring the options of plotting data using the sp package. It
is, after some trial and error, not too difficult to produce nice
looking maps combining polygon, line and grid data with spplot. One
thing I haven't been able to figure out though is the use of the
argument 'formula' in the spplot.grid function. Does anyone has a good
example explaining its use?
Best regards
Paulo van Breugel
_______________________________________________
R-sig-Geo mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Hi,
I've been using spplot a lot over the past two years and I've never used
the formula argument. Why do you want to use it? If you are determined
to use it, the documentation of spplot says :
formula optional; may be useful to plot a transformed value.
Defaults to z~x+y for single and z~x+y|name for multiple attributes; use
e.g. exp(x)~x+y|name to plot the exponent of the z-variable
Why the formula argument looks like this can be traced back to the fact
that the lattice function levelplot is used to make the plots. See
?levelplot for extra information (see the x argument).
cheers and good luck!
Paul
--
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone: +31302535773
Fax: +31302531145
http://intamap.geo.uu.nl/~paul
_______________________________________________
R-sig-Geo mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
