


LL2XY - convert latitude and longitude coordinates to x and y
Usage:
[x,y]=ll2xy(lat,lon)
See also MAPLL, MAPXY

0001 function [x,y]=ll2xy(lat,lon); 0002 %LL2XY - convert latitude and longitude coordinates to x and y 0003 % 0004 % Usage: 0005 % [x,y]=ll2xy(lat,lon) 0006 % 0007 % See also MAPLL, MAPXY 0008 0009 lon=lon+360; % to have 0<lon<360 0010 0011 re = 6378137.0; % WGS84 0012 e2 = 0.00669437999015; % WGS84 0013 sn=-1.0; % because it's southern hemisphere 0014 0015 a=re; 0016 e=sqrt(e2); 0017 0018 phi = sn*lat*pi/180; 0019 lambda = lon*pi/180; 0020 0021 qp = 1 - (1-e2)/2/e*log((1-e)/(1+e)); 0022 %m=cos(phi)/sqrt(1-e2.*sin(phi)*sin(phi)); 0023 q=(1-e2)*(sin(phi)./(1-e2*sin(phi).^2)-0.5/e*log((1-e*sin(phi))./(1+e*sin(phi)))); 0024 rho = a*sqrt(qp-q); 0025 x = rho.*sin(lambda); 0026 y = - sn*rho.*cos(lambda); 0027 0028 0029 %lon=lon-360; % to recover the initial longitude 0030