inverse overlay combination A and (not B) of polygon and SpatialPixelDataFrame

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-sig-geo/attachments/20110217/43e1c8b1/attachment.pl>
Dear OSGEO list members,
Please take a look at www.osgeo.org to find out what osgeo means.
I have installed R-10.1 on windows XP. My problem:
The current version is 2.12.1
I have a polygon (the border of the Zuiderzee (=IJmeer?!) in the 
Zuiderzee is the historic name of the sea that is now IJsselmeer before
the Afsluitdijk was built (zee = "sea", becoming meer = "lake"), + the
areas that have been reclaimed since and used to be sea (Flevopolders,
Noordoostpolder).
Netherlands) and a SpatialPixelsDataFrame, containing genetic similarities 
among watersnakes across geography, bound to the convex hull curve of the 
sampling coordinates, around the Zuidersee). What I want, is to cut off the 
spatial grid by the edges of the Zuiderzee.
What I so far only got by trying the overlay function is:
###
zuiderzee_union # the polygon of the Zuiderzee
rinsl.SPix.clus.clip # the SpatialPixelDataFrame
sel=!is.na(overlay(rinsl.SPix.clus.clip, zuiderzee_union))
###?  A?  %over%?  B
rinsl.SPix.clus.union.clip <- rinsl.SPix.clus.clip[sel,]
##
This operation cuts out the area, which lies in the Zuiderzee - but I just 
need the inverse (I assume acc. to the A and (not B) boolean opeation),?  
the area which is outside the Zuiderzee.
Have you tried:

rinsl.SPix.clus.union.clip <- rinsl.SPix.clus.clip[!sel,]
Any help is much apprecited!
Many Thanks in advance!

########################################################################
Axel Hille (Dr. rer. nat.)
population genetic and geography
D-33605 Bielefeld
########################################################################

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Edzer Pebesma
Institute for Geoinformatics (ifgi), University of M?nster
Weseler Stra?e 253, 48151 M?nster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de