function amerc
% AMERC: set DataAspectRatio to Mercator proportions at figure centre
% AMERC is called after creating a figure where the x and y axes are
% longitude and latitude in degrees
  
% $Id: amerc.m,v 1.1 1999/05/20 07:30:45 mansbrid Exp $
% Copyright J. V. Mansbridge, CSIRO, Thursday May 20 17:27:16 EST 1999

ylim = get(gca,'ylim');
set(gca,'DataAspectRatioMode','manual');
set(gca,'DataAspectRatio',[1/(cos(mean(ylim)*pi/180)) 1 1]);
axis manual; hold on;
