Why points inside a polygon can't be found completely by using "Inpolygon"

Dear all,

I would like to find a set of points (red points in the below figure) whether inside another bunch of points (blue points in the below figure). Thus, I use the "inpolygon" command, but stragely only some of points located inside the polygon are returned. Why it happens? how to fix it?

load data.mat
ind=inpolygon(source_xtheta,source_ytheta,xloc,yloc);
figure;
plot(xloc,yloc,'bo');
hold on;
plot(source_xtheta(ind),source_ytheta(ind),'r*');

Figure 1: Problem Definition

Figure 2: Matlab Result

Answer 1

[KSSV]

load('data.mat')
idx = boundary(xloc,yloc) ;  % pick the boundary points which form a polygon
ind=inpolygon(source_xtheta,source_ytheta,xloc(idx),yloc(idx));
figure;
plot(xloc,yloc,'b.');
hold on;
plot(source_xtheta(ind),source_ytheta(ind),'r*');