I have a raster with longitudes and latitudes for the US with meteorological data (for about 100k grid points). I would like to get the time zone for each point in order to transform the time to local time. Here is how my raster look like:
> raster class : SpatialPointsDataFrame features : 95025 extent : -179.9979, 179.9918, 1, 85.33336 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0 variables : 1 names : narr.a_221_20141002_1200_000.sub min values : 0 max values : 100
This problem is somewhat similar to https://stackoverflow.com/questions/23414340/convert-to-local-time-zone-using-latitude-and-longitude, except that I have lots of points. The suggested solution there does not work as the Google API accepts only limited number of requests per day and I do not think that the brute force solution would be the most efficient.
I am an absolute beginner in geographical data, but familiar with R, so I need a solution which works in R.