On Thu, 14 Feb 2008, Mathieu Basille wrote:

Thanks Rick for the hints.

I have to admit, however, that it is so far a huge failure. I have been
able to play a bit with the color key (arg 'colokey' that sets the
position, the colors, the tick marks, height & width, etc.) and the
color of one map (arg 'col.regions', for finite values of the layer),
but I'm still unable to
1) have different scales for different layers (i.e. one color key per
layer);

This suggests that you really should not be using lattice graphics, because they are specifically written for conditional plots, so necessarily on the same scale for comparision

2) color NA with a non-contiguous color from other finite values. From
my different tests, NA are always white (I wish I could fill them in red
for example, with finite values in a gradient of grey).

In addition, I'm totally lost in the help pages of xyplot and levelplot
(lattice), and the graph gallery of sp didn't help neither.

Any other resource or tutorial for this?

There is Paul Murrell's R Graphics book (Chapman & Hall/CRC), and lattice author Deepayan Sarkar's forthcoming lattice book (Springer useR series), but lattice is, I think, not what you want if you want to control things yourself. Just use base graphics and build things up layer by layer.

Lattice is superb for what it is designed for, by the way, say conditioning earthquake location by depth as the classic example, or plotting anisotropic variograms by direction.

Roger

Thanks in advance,
Mathieu.


Rick Reeves a écrit :
Mathiu:

The attached use case might help: It is not exactly what you are looking
for, but the last map
demonstrates use of the spplot function to create a 'display list' that
plots vector and raster
data layers on a single map. Also some hints on creating a map scale and
legend.

http://nceas.ucsb.edu/scicomp/GISSeminar/UseCases/MapProdWithRGraphics/OneMapProdWithRGraphics.html


Regards,
Rick Reeves

Mathieu Basille wrote:
Hello everyone,

I'm not very familiar with visualization of spatial objects in R,
especially with the possibilities of the spplot function...

I have a SpatialPolygonsDataFrame and I'd like to obtain a map with a
specific scale for each layer (not in the geographic space, but in the
data), instead of the same one for every one. In my case, the layers
represent different variables, not on the same scale (e.g. elevation
and rain).

Additionally, I'd like to represent NA's with a particular color (say
black so that we can see immediately where they occur).

I guess these 2 issues are somehow related, but I didn't manage to
solve them. The help pages of spplot or xyplot didn't really help...

Any hint how to do that?
Thanks in advance,
Mathieu.


> version
platform       i486-pc-linux-gnu
svn rev        43537
version.string R version 2.6.1 (2007-11-26)
sp: sp_0.9-19




--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: [EMAIL PROTECTED]
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