function out = worldlo(request)

% WORLDLO returns data from the WORLDLO atlas data file
% 
%   WORLDLO types a list of the atlas data variables in the WORLDLO Mat-file to
%   the screen.
%   
%   s = WORLDLO('request') returns the requested variable.  Valid requests 
%   are 'POline', 'POpatch', 'POtext', 'PPpoint', 'PPtext', 'DNline', 
%   'DNpatch', 'oceanmask' and 'gazette'.  This command can be used as an 
%   argument to other commands, such as DISPLAYM(WORLDLO('POline')).
%  
%   The WORLDLO atlas data file contains vector data equivalent to a scale 
%   of 1:30,000,000 covering drainage, political/ocean boundaries and 
%   populated places. The data is in Geographic Data Structures for 
%   four types of objects: patches, lines, points and text. It is suitable
%   for global continental displays.
%
%   See also WORLDHI, COAST, USAHI, USALO, WORLDLO.MAT, OCEANLO.MAT

% Copyright 1996-2000 Systems Planning and Analysis, Inc. and The MathWorks, Inc.
% $Revision: 1.5 $  $Date: 2000/01/18 02:05:03 $


if nargin == 0
	load('worldlo','description')

	disp('    ')
	disp('WORLDLO atlas data:')
	disp('    ')
	disp(description)
	disp('    ')
	disp('  Geographic Data Structures: ')
	disp('    ')
	disp('    POline        - Political Boundaries and coastlines as lines')
	disp('    POpatch       - Countries as patches')
	disp('    POtext        - Names of countries as text')
	disp('    PPpoint       - Major Cities as points')
	disp('    PPtext        - Major Cities as text labels')
 	disp('    DNline        - Major rivers as lines')
	disp('    DNpatch       - Major lakes as patches')
	disp('    oceanmask     - Oceans as patches')
	disp('    gazette       - Country and City names')
	disp('    ')
	return
end

switch request
case 'oceanmask'
	load oceanlo
	out = oceanmask;
otherwise
	load('worldlo',request)
	if exist(request) ~= 1
		error([ request ' not found in WORLDLO.MAT'])
	end
	
	eval(['out = ' request ';'])
end
