tion 
% 
% |[lati,loni] = pspath(lat,lon,spacing)| connects the geographic points |lat,lon| 
% by a path whose points |lati,loni| are separated by spacing meters. If input
% coordinates are geo coordinates, output coodinates are also geo coordinates. 
% 
% |[xi,yi] = pspath(x,y,spacing)| connects the polar stereographic points |x,y| 
% by a path whose points xi,yi are separated by spacing meters. If input
% coordinates are polar stereographic coordinates, output coodinates are also 
% polar stereographic co