Dear R-SIG-GEO list
I want to aggregate the mean value of points in a polygon using the over
function.
#Read the shapefile with the measurements
shapefilename <-
paste(shapefiledir,shortNameIndicator,"_",production.date,sep="")
point.shapefile <- readShapePoints(paste(shapefilename,".shp",sep=""))
names(slot(point.shapefile,'data')) <- c("ID",shortNameIndicator)
#aggregate per polygon by mean and save as shapefile
aggregate.data<-over(studyzone,point.shapefile,fn=mean)
row.names(aggregate.data) <- row.names(aggregate.data)
outPolDF <- SpatialPolygonsDataFrame(studyzone,aggregate.data,match.ID=T)
writePolyShape(outPolDF,paste(shapefiledir,shortNameIndicator,"_poly_",production.date,".shp",sep=""))
While this works using the mean function I am unsure how to proceed for a
weighted mean - does anyone have a suggestion?
Many thanks
Els
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