how to mark and print the intersecting coordinates of two lines

49 次查看（过去 30 天）
Anitha Limann
Anitha Limann 2021-10-9
评论： Star Strider 2021-10-10
I have x1,y1 and x2, y2 data sets that give me two lines graphs.
I want to find the intersecting point of these two lines and and print it on the graph.
I tried following different functions like intesect but did not work.
Could someone please help me with this?
  2 个评论
Matt J
Matt J 2021-10-10
Ran in:
Since it is discrete data, you need a more formal definition of what it means for them to "intersect". Suppose we have
[x1,y1,x2]=deal([0,1]);
y2=[1,0];
plot(x1,y1,'--x', x2,y2,'-o')
These seem to intersect at (x,y)=[0.5,0.5] but only because I've chosen to connect the points with straight lines instead of some other kind of connecting curve. Is that what you want?
Anitha Limann
Anitha Limann 2021-10-10
Yes. i have these datasets
x1=[10,20,30,40,50,75,100,125,150,175,200,225,250,275];
t1=[1.6,3.2,4.8,6.4,8,12,16,20,24,28,32,36,40,44];
x2=[150,175,200,225,250,275,300,325,350,375,400];
t2=[26.62,29.69,32.75,35.82,38.89,41.96,45.02,48.09,51.16,54.23,57.29];
some point values. where i get this graph
so i want to find this intersecting point and print it on the graph.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2021-10-10
Ran in:
Much depends on what ‘x1’, ‘y1’ and the rest are.
One approach (sssuming multiple intersections, although thiis will also work for only one intersection) would be —
x1 = linspace(-2, 15);
y1 = 2 + 3*x1;
x2 = linspace(-10, 10);
y2 = (x2-2).^2;
xq = linspace(min([x1,x2],[],2), max([x1,x2],[],2)); % Create Common 'x' Vector
y1q = interp1(x1, y1, xq, 'pchip','extrap'); % Interpolate To It
y2q = interp1(x2, y2, xq, 'pchip','extrap'); % Interpolate To It
idx = find(diff(sign(y1q-y2q))); % Approximate Indices Of Intersections
for k = 1:numel(idx)
idxrng = max(1,idx(k)-2) : min(numel(xq),idx(k)+2); % Index Range
xi(k) = interp1(y1q(idxrng)-y2q(idxrng), xq(idxrng), 0); % Interpolate X-Intersection
yi(k) = interp1(xq(idxrng), y1q(idxrng), xi(k)); % Interpolate Y-Intersection (Either Y-Vector Will Work)
end
Intercepts = [xi; yi]
Intercepts = 2×2
0.3001 6.7004 2.9004 22.1012
figure
plot(x1, y1)
hold on
plot(x2, y2)
plot(xi, yi, '+r', 'MarkerSize',10)
hold off
grid
legend('y1','y2','Intersections', 'Location','best')
Experiment to get the desired result.
.

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Interpolation 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