maskvar
Function to mask a variable using another variable to mask it. Only need to share at least 1 dimension with the same size (no need same name)
maskvar(values, filename, varparameters)
values= [maskfilename]:[maskvarn]:[dimsmask]:[timename]
   [maskfilename]= file with the mask
   [maskvarn]= name of the variable with the mask
   [dimsmask]= ',' list of [dimn]|[sec] to use for slicing [maskvar]
     [sec]: section
       * [integer]: which value of the dimension
       * -1: all along the dimension
       * -9: last value of the dimension
       * [beg]@[end]@[frq] slice from [beg] to [end] every [frq]
     * NOTE: no value provided is for all dimension range
   [maskvalue]= value to use for maskking ('mask' value for using an already masked variable)
filename= netCF file name
varparameters= [varn]|[dimsmask]
   [varn]: variable name
   [samedimsmask]: ',' list of name of dimensions which fits [maskvarn] slice
$ python ${pyHOME}/nc_var.py -o maskvar -f SouthAm_Climzones.nc -S 'geo_em.d01.nc:LANDMASK:Time|0:0' -v region:lon,lat
  SouthAm_Climzones.nc
     lat = 999;
     lon = 649;
     int region(lat, lon)
   geo_em.d01.nc
     Time = UNLIMITED ; // (1 currently)
     west_east = 649;
     south_north = 999;
     float LANDMASK(Time, south_north, west_east)