source: issm/oecreview/Archive/19101-20495/ISSM-19296-19297.diff

../trunk-jpl/src/m/psl/sharmonics.m

@@ +1 @@
+function sh = sharmonics(lat,lon,lMax) 
+
+%SHarmonics :: a function to compute (ortho-)normalized shperical harmonics 
+% 
+%USAGE: sh = sharmonics(lat,lon,lmax); 
+%
+%lat (latitude in [0,180] degrees from the north pole) 
+%lon (longitude in [0 360] degrees) 
+%lmax (maximum SH degree you wish to compute) 
+%
+%sh (spherical harmonics of degree and orders up to "lmax"... 
+%...numbered as 1(l=0), 2(l=1,m=-1), 3(l=1,m=0), 4(l=1,m=1)...) 
+%
+
+q=0;
+%       
+lat=lat*pi/180;
+lon=lon*pi/180; 
+
+%ortho-normalized SH 
+for l=0:lMax
+        plm = legendre(l,cos(lat),'norm');
+   for m=-l:l 
+                if(m<0) 
+                        sh(:,1+q)=(-1)^(abs(m))*2.*plm(abs(m)+1,:)'.*sin(abs(m).*lon);
+      elseif(m==0)
+         sh(:,1+q)=sqrt(2)*plm(abs(m)+1,:)';
+      else
+         sh(:,1+q)=(-1)^(abs(m))*2.*plm(abs(m)+1,:)'.*cos(abs(m).*lon);
+      end
+      q=q+1;
+   end
+   %disp(['Spherical Harmonics of degree ',num2str(l),' (of ',num2str(lMax),') computed!']);
+end
+disp(['Spherical Harmonics of degree and orders up to ',num2str(lMax),' computed!']);
+
+