Triangulation within specified region

I am trying to triangulate a specified region along a 2d plane. The region i wish to tringualte is specified by x and y cooridantes and the lines joining each of these points. However when I use delaunyTriangulation it triangulates the entire region, including the parts I wish to leave out. I have inserted an image below.

Is there anyway to specify the boundary or region of which I would like to triangulate or remove the large unwated trinagles from the triangulation?

Thanks

[darova]

If you have boundaries of your region use inpolygon() to indicate points inside and then triangulation

[Robin Pillar]

I already have the points which I have included an image below. What I want is to triangulate the narrow region between the points but not outside as keeps happening

[darova]

Can you please attach this data?

Answer 1

[KSSV]

Read about delaunayTriangulation , you can provide edge constraints. On providing these constraints; you can avoid such triangles.

DT = delaunayTriangulation(x,y,C)

[Robin Pillar]

I've tried this and used the edges which are the outline of the shape I've shown above as the constraints and I still get it triangulating the area outside the narrow region I want

[KSSV]

Attach your data....I can work on it on Monday only...weekend :)

[Robin Pillar]

Data attached

[KSSV]

YOu have other option: explore alphashape

data = importdata('data.txt') ; 

x = data(:,1) ; y = data(:,2) ; 

% dt = delaunayTriangulation(x,y) ;

shp = alphaShape(x,y) ;
shp.Alpha = 0.04 ; 
plot(shp)

YOu can play around with value of shp.Alpha. Meanwhile I will try delaunay on the data and let you know. Actually the points (x,y) are not in order, we need to arrange them in order to provide constraints.

[KSSV]

I have arranged the points Point.txt in an order and run delaunayTriangulation. I am attaching the data and code here.

data = importdata('data.txt') ; 
x = data(:,1) ; y = data(:,2) ; 
p = (1:length(x))' ; 
C = [p(1:end-1) p(2:end)] ; 

dt = delaunayTriangulation(x,y,C) ; 
figure
triplot(dt)

xnew = dt.Points(:,1) ; ynew = dt.Points(:,2) ;
isInside = isInterior(dt) ;         % Find triangles inside the constrained edges
tri = dt(isInside, :);              % Get end point indices of the inner triangles
figure
triplot(tri,xnew,ynew);      

[darova]

KSSV, how did you order those points? (Manually?)

[KSSV]

I used another software which my colleague uses...:)