function valid = isValidProj(proj, fieldNames)
%ISVALIDPROJ True for a PROJ structure containing FIELDNAMES.
%
%   VALID = ISVALIDPROJ(PROJ, FIELDNAMES) returns 1 if PROJ is a structure
%   containing FIELDNAMES.
%
%   See also ISGEOTIFF, ISMSTRUCT.

%   Copyright 1996-2003 The MathWorks, Inc.
%   $Revision: 1.1.6.1 $  $Date: 2003/08/01 18:24:21 $

if ~isstruct(proj)
   valid = false;
   return
else
   valid = true;
end
for i=1:length(fieldNames);
   if (~isfield(proj,fieldNames(i)))
     valid = false;
     break;
   end
end