Changeset 2079

Timestamp:

09/02/09 09:55:01 (16 years ago)

Author:

Mathieu Morlighem

Message:

Readded ll2xy: results differ from mapll... to be investigated

Location:

issm/trunk/src/m/utils/LatLong

Files:

• ll2xy.m (added)
• mapll.m (modified) (3 diffs)

issm/trunk/src/m/utils/LatLong/mapll.m

@@ -1 @@
-function  [x,y]=mapll(alat,alon,hem);
+function  [x,y]=mapll(lat,lon,hem);
 %MAPLL - convert latitude and longitude into x and y
 %
@@ -10 +10 @@
 %   See also MAPXY, LL2XY
 
-re=6378137.0; 
+%some corrections
+lon=lon+360;       % to have 0<lon<360
+
+%WGS84
+re=6378137.0;
 e2= 0.00669437999015;
-
 e=sqrt(e2);
 
 %Standard parallel - latitude with no distortion = -71.
-slat=71;
-sn=-1.0;
-xlam=0;
-
 if hem==1,
-   xlam=45;
+        %Northern hemisphere
         sn=1;
         slat=70;
+        xlam=45;
+else
+        %Southern Hemisphere
+        sn=-1.0;
+        slat=71;
+        xlam=0;
 end
 
-alat=sn*alat;
-alon=sn*alon;
-alat=alat/180*pi;
-alon=alon/180*pi;
+lat=sn*lat*pi/180;
+lon=lon*pi/180;
 
-rlat=alat;
+rlat=lat;
 slat=slat/180*pi;
 xlam=xlam/180*pi;
@@ -43 +46 @@
 cm=cos(slat)./sqrt(1.0-e2*(sin(slat).^2));
 rho=re*cm.*t1./t2;
-x= rho*sn.*sin((alon+xlam));
-y=-rho*sn.*cos((alon+xlam));
+x= rho*sn.*sin((lon+xlam));
+y=-rho*sn.*cos((lon+xlam));