[R-sig-Geo] Working with raster data in R

[Wall, Wade A ERDC-RDE-CERL-IL]

Hi all,

I am new to working with raster data, so forgive my ignorance up front.

I have two raster files that I have imported into R using raster(). The second raster file is a subset of grids within the first raster file that covers an area. I would like to create an object (dataframe?) with the values from the first raster based on the spatial coordinates of the second raster, but cannot figure out how to do this, although it seems to be fairly simple.

Secondly, is there a way to bootstrap values from a raster file. For example, I would like to bootstrap X number of grid values and calculate the mean value. 

Basically, I want to know if the values in the second raster (the subset) are less than the values in the first raster and want to test this through bootstrapping the first raster. If there is a better way, please let me know.

Thanks,

Wade A. Wall
US Army ERDC-CERL
P.O. Box 9005
Champaign, IL  61826-9005
1-800-872-2375 ext. 7320
1-217-353-6511 ext. 7320