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%% Using alphaShape Objects % This example shows how to change an alpha shape object and compute useful % quantities that describe the alpha shape. % Copyright 2015 The MathWorks, Inc. %% % Create and plot a set of 2-D points. x = gallery('normaldata',50,1,1); y = gallery('normaldata',50,1,2); plot(x,y,'.') %% % Create and plot an alpha shape using an alpha radius of 0.7. shp = alphaShape(x,y,0.7); plot(shp) %% % Change the alpha radius to 0.5 to tighten the boundary around % the set of points. shp.Alpha = 0.5; plot(shp) %% % Query the number of regions that make up the new alpha shape. numRegions(shp) %% % Suppress the smaller of the two regions. shp.RegionThreshold = 1; plot(shp) %% % Compute the perimeter and area of the remaining region. regionperims = perimeter(shp) regionareas = area(shp)