making read_mask.m more robust

[wilkin]

editmask.m throws some errors due to conflicts with new or incomplete grid files when variable hraw has not been loaded.

These can be solved by making a few changes to read_mask.m

A grid file may have a variable hraw that has not been filled with data. This will cause an error in editmask. I suggest test for the case hraw has an empty dimension:

case {Vname.hraw}
  got.hraw=true;
  if any(V.Variables(n).Size==0)
     got.hraw=false;
  end

read_mask presently only checks for spherical in the form of a character, and always returns false even when spherical=1 (numeric). Make this robust and compatible with both conventions with:

 if (got.spher)
    spher=nc_read(ncfile,Vname.spher);
    if ischar(spher)
       if strcmpi(spher,'T')
          spherical=true;
       end
    else
       spherical=spher;
    end
  end

[arango]

Yes, thank for reporting these problems. Now, we have:

    case {Vname.hraw}
      if ~any(V.Variables(n).Size == 0),
        got.hraw=true;
      end

and

if (got.spher),
  spherical=nc_read(ncfile,Vname.spher);
  if (ischar(spherical)),
    if (spherical == 'T' || spherical == 't')
      spherical = true;
    else
      spherical = false;
    end
  end
end