The EASE-2 grid is used for a number of NASA datasets including SMAP. It is described in the following paper:
Brodzik, M. J., Billingsley, B., Haran, T., Raup, B., & Savoie, M. H. (2012). EASE-Grid 2.0: Incremental but Significant Improvements for Earth-Gridded Data Sets. ISPRS International Journal of Geo-Information, 1(3), 32–45. http://doi.org/10.3390/ijgi1010032
Files with the centre coordinate of each cell for EASE-2 grids at different resolutions are available from https://nsidc.org/data/ease/tools.html as well as tools for conversion.
To read these files into Python the following steps can be used:
- Download the relevant gridloc file.
The FTP link for the grid location files is: ftp://sidads.colorado.edu/pub/tools/easegrid2/
For this example I’ve chosen the 36km cylindrical EASE-2 grid (gridloc.EASE2_M36km.tgz)
- Un-tar using:
tar -xvf gridloc.EASE2_M36km.tgz
- Read the files into Python:
import numpy # Read binary files and reshape to correct size # The number of rows and columns are in the file name lats = numpy.fromfile('EASE2_M36km.lats.964x406x1.double', dtype=numpy.float64).reshape((406,964)) lons = numpy.fromfile('EASE2_M36km.lons.964x406x1.double', dtype=numpy.float64).reshape((406,964)) # Extract latitude and longitude # for a given row and column grid_row = 46 grid_column = 470 lat_val = lats[grid_row, grid_column] lon_val = lons[grid_row, grid_column]