Function for accessing elevation data from the USGS epqs
get_epqs(locations, units = c("meters", "feet"))
A SpatialPointsDataFrame of the location(s) for which you wish to return elevation. The first column is Longitude and the second column is Latitude.
Character string of either meters or feet. Only works for 'epqs'
a SpatialPointsDataFrame with elevation added to the data slot