# DaymetR – gridded data extension

Short recap: Daymet is a collection of algorithms and computer software designed to interpolate and extrapolate from daily meteorological observations to produce gridded estimates of daily weather parameters - as concisely described on the Daymet website.

I’m extensively using daily meteorological data to drive a grassland growth model and quick and easy access to this data is therefore key. Although I previously coded a script to deal with single pixel data extraction I now updated my DaymetR package to include gridded (tiled) data downloads through the specification of a region of interest (top left / bottom right) or single point location.

The script has the following syntax:

download.Daymet.tiles(lat1=36.0133,
lon1=-84.2625,
lat2=NA,
lon2=NA,
start_yr=1980,
end_yr=2012,
param="ALL")

If only the first set of coordinates is provided (lat1 / lon1) the tile in which these reside is downloaded. If your location / region of interest [defined by a top left (lat1 / lon1) and bottom right (lat2 / lon2) coordinate set] falls outside the scope of the DAYMET data coverage a warning is issued. All tiles covering the region of interest are downloaded for their respective parameters, e.g. minimum and maximum temperature (see bitbucket documentation for details).

This final addition is a spatial extension of the previous code, serving primarily the spatial scaling needs of my modelling exercises. All code can be found on through my software page or by following this direct link to my bitbucket page. I hope this might serve other people in the R community.