Hi Laetitia, Try turning your .ppp object into a spatial grid data frame, then convert it to a raster. The 'extract' function should then work if your projections are correct.
Jesse your.ppp.object<-as.SpatialGridDataFrame.im(your.ppp.object) rast.ppp.object<- raster(your.ppp.object) #Convert to a raster grid output<- extract(rast.ppp.object, polys) ----- -------------------------------------------------------- Jesse D Berman, PhD Yale University School of Forestry and Environmental Studies Post-Doc Fellow -- View this message in context: http://r-sig-geo.2731867.n2.nabble.com/overlay-a-ppp-object-and-a-SpatialPolygon-tp7584755p7584775.html Sent from the R-sig-geo mailing list archive at Nabble.com. _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
