We need the following in place before we can proceed with the steps required for the recipe:
- From the worldclim website, download the current raster data (http://www.worldclim.org/current) for min and max temperatures (only the raster for max temperatures will be used for this recipe). Alternatively, use the ones provided in the book datasets (data/chp01). Each of the two archives (data/tmax_10m_bil.zip and data/tmin_10m_bil.zip) contain 12 rasters in the BIL format, one for each month. You can look for more information at http://www.worldclim.org/formats.
- Extract the two archives to a directory named worldclim in your working directory.
- Rename each raster dataset to a name format with two digits for the month, for example, ...