%% Query Points Inside and Outside of 2-D Alpha Shape
% Create a set of 2-D points.

th = (pi/12:pi/12:2*pi)';
x1 = [reshape(cos(th)*(1:5), numel(cos(th)*(1:5)),1); 0];
y1 = [reshape(sin(th)*(1:5), numel(sin(th)*(1:5)),1); 0];
x = [x1; x1+15;];
y = [y1; y1];

%
% Create and plot an alpha shape using an alpha radius of 2.5.

shp = alphaShape(x,y,2.5);
plot(shp)

%
% Create a Cartesian grid of query points near the alpha shape.

[qx, qy] = meshgrid(-10:2:25, -10:2:10);

%
% Check if the query points are inside of the alpha shape, and if so, plot them red. Plot the query points that lie outside of the alpha shape in blue.

in = inShape(shp,qx,qy);
plot(shp)
hold on
plot(qx(in),qy(in),'r.')
plot(qx(~in),qy(~in),'b.')

% Copyright 2015 The MathWorks, Inc.