Calculate the largest, smallest diameter and the centroid of a polyshape (irregula rpolygon) from a set of points

8 次查看（过去 30 天）
Tesla
Tesla 2022-9-8
评论： Matt J 2022-9-9
I have a set of points (x,y) for a polyshape (almost 120 coordinates), I want to find the largest, smallest diameter and the centroid of this irregular polygon.

请先登录，再回答此问题。

采纳的回答

Matt J
Matt J 2022-9-8
编辑：Matt J 2022-9-8
Ran in:
For the centroid, polyshape has a method centroid.
If the min and max feret diameters are what you want, then one approach would be,
pgon=nsidedpoly(4,'Radius',0.5); %input polyshape
fun=@(theta) feretDiam(pgon.Vertices,theta);
Theta=linspace(-pi,pi,1e4);
%Min Diameter
[~,i0]=min(fun(Theta));
[thetamin,minDiam]=fminsearch(@(t)fun(t),Theta(i0));
minDiam
minDiam = 0.7071
%Max Diameter
[~,i0]=max(fun(Theta));
[thetamax,maxDiam]=fminsearch(@(t)-fun(t),Theta(i0));
maxDiam=-maxDiam
maxDiam = 1.0000
function d=feretDiam(V,theta)
p=V*[cos(theta);sin(theta)];
d=max(p,[],1)-min(p,[],1);
end
  14 个评论
显示 12更早的评论
Tesla
Tesla 2022-9-9
Ran in:
Can you please tell me what the problem in this code:
pgon=nsidedpoly(4,'Radius',0.5); %input polyshape
fun=@(theta) feretDiam(pgon.Vertices,theta);
[~,xmin,ymin]=fun(thetamin);
Unrecognized function or variable 'thetamin'.
[~,xmax,ymax]=fun(thetamax);
plot(pgon);
line(xmin,ymin,'LineStyle','--');
line(xmax,ymax,'LineStyle','--');
function [d,xb,yb]=feretDiam(V,theta)
udir=[cos(theta);sin(theta)];
p=V*udir;
umax=max(p,[],1);
umin=min(p,[],1);
d=umax-umin;
if nargout>1
umax=udir.*umax;
umin=udir.*umin;
xb=[umin(1,:);umax(1,:)];
yb=[umin(2,:);umax(2,:)];
end
end
Matt J
Matt J 2022-9-9
Can you please tell me what the problem in this code:
The code doesn't include the lines that compute thetamin and thetamax.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Elementary Polygons 的更多信息

标签

产品


版本

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by