Hi ZhG,
Here is some code that shows a few different ways of getting the perimeter of triangles. It first just shows the lengths of each edge in the Delaunay Triangulation. Then it sums up the perimeter of the boundary of the triangulation. Then it shows the perimeter of each face (displayed in red).
x = [ 16 16 16 17 18 19 19 20 21 21 23 23 23 ]
y = [ 151 369 397 208 84 93 177 326 112 243 164 213 390 ]
DT = delaunayTriangulation(x',y')
figure, triplot(DT), hold on
edges = DT.edges;
edgeLens = zeros(size(edges,1),1);
for i = 1:size(edges,1)
thisEdgePts = DT.Points(edges(i,:),:);
edgeCpt = mean(thisEdgePts,1);
edgeLen = sqrt(sum(diff(thisEdgePts,[],1).^2));
edgeLens(i) = edgeLen;
text(edgeCpt(1),edgeCpt(2),sprintf('%0.1f',edgeLen),'HorizontalAlignment','center')
end
outerBoundaryPerim = sum(edgeLens(ismember(DT.edges, DT.freeBoundary,'rows')))
for i = 1:size(DT.ConnectivityList,1)
thisVerts = DT.Points(DT.ConnectivityList(i,:),:);
faceEdgeLens = sqrt(sum(diff(thisVerts([1:end 1],:),[],1).^2,2));
facePerim = sum(faceEdgeLens);
faceCpt = mean(thisVerts,1);
text(faceCpt(1),faceCpt(2), sprintf('%0.1f',facePerim),'Color','r')
end
Did that help you out and answer your question?
