spplot: no boundary lines for polygons

I have a complex shape file imported to R via rgdal
as a SPolDF. I want to display continuous attributes
with a color key but the black boundaries
of the polygons, which are small in general, introduce
"too much black" in the plot and the spatial variation
of the attribute is not correctly displayed.

What I do is
spplot(MMAMBCGUcombi["DIFPW"])

(BTW, where is the code for fig. 3.6 in the book? Perhaps I should be
using plot() instead of spplot(), but cannot find how to select
the actual atribute in the SPolDF in plot())

Is there any way of not plotting the boundaries of the polygons?

Thanks

Agus

Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
LLuis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
email: Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster


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