Finding Areas for Constrained 2D Delaunay Triangulation

Hello,

I am having issues with finding the coordinates and the areas of a constrained 2D delaunay triangulation. I have managed to do that if the problem is not constrained, but the constrain gives strange answers for my vertixes, and that makes hard for me to find the areas.

Thanks for the help!

The code that I am uploading is an example that I took from the internet, since it is slightly simpler than my original code.

figure()
axis([-1 17 -1 6]);
axis equal
P = [0 0; 16 0; 16 2; 2 2; 2 3; 8 3; 8 5; 0 5];
C = [1 2; 2 3; 3 4; 4 5; 5 6; 6 7; 7 8; 8 1];
DT = delaunayTriangulation(P,C);
patch(P(:,1),P(:,2),'-r','LineWidth',2,'FaceColor',...
     'none','EdgeColor','r');
 % Compute the in/out status.
IO = isInterior(DT);
hold on;
axis([-1 17 -1 6]);
triplot(DT(IO, :),DT.Points(:,1), DT.Points(:,2),'LineWidth', 2)
hold off;
v1 = P(tri(:,2), :) - P(tri(:,1), :);

[darova]

Can you calculate area of each triangle?

Answer 1

[Dimo Iordanov]

Yeah I managed to do that by using the code below.

for i=1:9
     x1 = DT.Points(DT.ConnectivityList(i,:),:);
     area(i) = 1/2.*abs((x1(2,1)-x1(1,1)).*(x1(3,2)-x1(1,2))-(x1(3,1)-x1(1,1)).*(x1(2,2)-x1(1,2)));
     b=area.*[1; 1; 1; 1; 1; 1; 1; 1];
end