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

Question

Jiali 2022-2-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1658140-why-points-inside-a-polygon-can-t-be-found-completely-by-using-inpolygon

编辑： KSSV 2022-2-25

采纳的回答： KSSV

data.mat

在 MATLAB Online 中打开

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

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Answer 1

KSSV 2022-2-25

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1658140-why-points-inside-a-polygon-can-t-be-found-completely-by-using-inpolygon#answer_904195

编辑：KSSV 2022-2-25

在 MATLAB Online 中打开

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*');