title: Zip Codes from Lat/Lon (batch query)
body: <p>I have a data.frame with 1500 latitude/longitude entries. I need to map these coordinates to their zip codes. Is there a way to do this besides entering them in one at a time to a geonames -type api? I would like a package in <code>R</code> that takes in a lat-lon combo and produces a zip code for every row of my data.frame. </p>