Zonal Statistics or Extracting Raster Data

Premise A surprising number of people is unaware that you can use GIS shapefiles in R.The maptools library imports .shp points, lines and polygons

Zonal Statistics Let's say you have a series of annual precipitation grids for a given site. Within this site you have a set of study plots and you want to extract precipitation values from each grid for each of your study plots. This is great application of zonal statistics. If you plots are points, zonal statistics will simply extract precipitation values for the location of each point. If your plots are lines or polygons, zonal statistics can be used to calculate the mean (or some other statistic) precipitation for each plot.

Skill Relevance and Usefulness