geod2cart

GEOD2CART Convert geodesic coordinates to cartesian coord.

   PT2 = geod2cart(PT1, CURVE, NORMAL)
   CURVE and NORMAL are both [N*2] array with the same length, and
   represent positions of the curve, and normal to each point.
   PT1 is the point to transform, in geodesic  coordinate (first coord is
   distance from the curve start, and second coord is distance between
   point and curve).

   The function return the coordinate of PT1 in the same coordinate system
   than for the curve.

   TODO : add processing of points not projected on the curve.
   -> use the closest end 

   See also
   polylines2d, cart2geod, curveLength

   ---------
   author : David Legland
   INRA - TPV URPOI - BIA IMASTE
   created the 08/04/2004.

0001 function point = geod2cart(src, curve, normal)
0002 %GEOD2CART Convert geodesic coordinates to cartesian coord.
0003 %
0004 %   PT2 = geod2cart(PT1, CURVE, NORMAL)
0005 %   CURVE and NORMAL are both [N*2] array with the same length, and
0006 %   represent positions of the curve, and normal to each point.
0007 %   PT1 is the point to transform, in geodesic  coordinate (first coord is
0008 %   distance from the curve start, and second coord is distance between
0009 %   point and curve).
0010 %
0011 %   The function return the coordinate of PT1 in the same coordinate system
0012 %   than for the curve.
0013 %
0014 %   TODO : add processing of points not projected on the curve.
0015 %   -> use the closest end
0016 %
0017 %   See also
0018 %   polylines2d, cart2geod, curveLength
0019 %
0020 %   ---------
0021 %   author : David Legland
0022 %   INRA - TPV URPOI - BIA IMASTE
0023 %   created the 08/04/2004.
0024 %
0025 
0026 t = parametrize(curve);
0027 N = size(src, 1);
0028 ind = zeros(N, 1);
0029 for i=1:N
0030     indices = find(t>=src(i,1));
0031     ind(i) = indices(1);
0032 end
0033 
0034 theta = lineAngle([zeros(N,1) zeros(N,1) normal(ind,:)]);
0035 d = src(:,2);
0036 point = [curve(ind,1)+d.*cos(theta), curve(ind,2)+d.*sin(theta)];