[R-sig-Geo] Aggregate using Shapefile

[Tiffany Smith]

Hi all,

I'm looking to use a shapefile to aggregate a raster layer. Here's what I have so far:

indexAL<-raster("myfile.nc")
ALshp<-readShapePoly("ALzipcodes.shp")
ALrst<-rasterize(ALshp,indexAL,fun=mean)

"indexAL" has a finer resolution than "ALrst", and I'd like to aggregate "indexAL" up to the scale of "ALrst" in a way that I'm able to create a map in the end. I've used "extract", but am not sure then how to map that output. "aggregate" doesn't seem flexible enough to use a shapefile (or raster layer). Any suggestions?

Thanks,
Tiffany