How to find the number of point inside the graph?

3 次查看（过去 30 天）
Ellina
Ellina 2015-5-20
评论： Andrei Bobrov 2015-5-21
Hello,
  • I have made a graph and inserted many random points.
  • I marked the point manually in orange color for points outside the graph and green color for points inside the graph
  • I wonder how can we calculate the number of points in green color automatically using only MATLAB code?
Thank you in advance

请先登录，再回答此问题。

回答（1 个）

Andrei Bobrov
Andrei Bobrov 2015-5-20
编辑：Andrei Bobrov 2015-5-20
x = [0,7, 18, 37,47,54,57.5,59,61.5,69,87,95,99,103,110]'/110; % Let this
y = [0, 15,43,53,42,20,7,0, 37, 61,56, 40.5, 24, 6, 0]'/61; % is arrays - your data
f = griddedInterpolant(x,y,'pchip'); % old MATLAB: pp = interp1(x,y,'pchip','pp');
% f = @(x)ppval(pp,x);
xx = rand(100,1);
yy = rand(100,1)*1.3; % points for check
t = f(xx) - yy > 0;
plot(0:.001:1,f(0:.001:1));grid on
hold on
plot(xx(t),yy(t),'g*');
plot(xx(~t),yy(~t),'r*');
  2 个评论
Ellina
Ellina 2015-5-21
Thank you so much.
The logical code,t helps me a lot.
I already plotted the graph but I don't know how to count automatically the number of green point.
Still trying my best to code it.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Directed Graphs 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by