Changeset 2271 for issm/trunk/src/m/utils/LatLong/mapll.m

Timestamp:

09/22/09 13:38:39 (16 years ago)

Author:

Eric.Larour

Message:

More flexible mapll and mapxy.
New change of axis: stereomap

File:

• issm/trunk/src/m/utils/LatLong/mapll.m (modified) (4 diffs)

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

@@ -1 @@
-function  [x,y]=mapll(lat,lon,hem);
+function  [x,y]=mapll(lat,lon,hem,varargin);
 %MAPLL - convert latitude and longitude into x and y
 %
@@ -10 +10 @@
 %   See also MAPXY, LL2XY
 
+%check number of arguments.
+if ~((nargin==3) | (nargin==5)),
+        mapllerrorusage();
+end
+
+%hem: must be either 's' or 'n'
+if ~ischar(hem),
+        error('mapll error message: hemisphere argument should be ''n'' or ''s''');
+end
+
+%check hem is either 'n' or 's': 
+if ~(hem=='s' | hem=='n'),
+        error('mapll error message: hem should be ''s'' or ''n''');
+end
+
+%set sn: 
+if hem=='s',
+        slat=71;
+        sn=-1.0;
+        xlam=0;
+else
+        slat=70;
+        sn=1.0;
+        xlam=45;
+end
+
+%set defaults for standard parallels and centre meridians.
+if nargin==5,
+        slat=varargin{1};
+        xlam=varargin{2};
+end
+
+
 %some corrections
 lon=lon+360;       % to have 0<lon<360
@@ -17 +50 @@
 e2= 0.00669437999015;
 e=sqrt(e2);
-
-%Standard parallel - latitude with no distortion = -71.
-if hem==1,
-        %Northern hemisphere
-        sn=1;
-        slat=70;
-        xlam=45;
-else
-        %Southern Hemisphere
-        sn=-1.0;
-        slat=71;
-        xlam=0;
-end
 
 lat=sn*lat*pi/180;
@@ -48 +68 @@
 x= rho*sn.*sin((lon+xlam));
 y=-rho*sn.*cos((lon+xlam));
+
+end
+
+function mapllerrorusage(),
+        help mapll
+end