Calculating grid cell corners
Hello,
I have data on a regular 0.5 degree lonlat grid, that is
dimensions:
y = 360 ;
x = 720 ;
variables:
double lat(y, x) ;
lat:_FillValue = NaN ;
lat:units = "degrees_north" ;
double lon(y, x) ;
lon:_FillValue = NaN ;
lon:units = "degrees_east" ;
double presence(y, x) ;
presence:_FillValue = NaN ;
presence:species = "Gadus morhua" ;
presence:coordinates = "lat lon" ;
The data are 1 or NaN and I would like to calculate the global sum of the area of the cells with value 1. However, cdo gridarea doesn't work because I do not have the grid cell corners.
Would CDO be able to construct the grid cell bounds/corners (and write them to a grid file?)? I could of course use the lon and lat to calculate all the grid cell areas myself, but I can imagine this is available in CDO somewhere which would save time 
Thank you in advance for your help,
Anne