Making a contour plot from x and y data
13 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Markus Similä
am 21 Jul. 2020
Kommentiert: Markus Similä
am 23 Jul. 2020
I have a two column vector containing x and y values. The y values have a high accuracy (many decimal points).
x ranges from 0 to 50000 and y from 0 to 14.
I need to use contourf to make a 2d representation of this data.
How can this be done?
6 Kommentare
Akzeptierte Antwort
Adam Danz
am 22 Jul. 2020
Bearbeitet: Adam Danz
am 22 Jul. 2020
The bivariate density can be computed using histcounts2. You'll need to specify either the number of bins or the bin edges for the x and y variables using one of the syntaxes below.
Here's what the solution will look like. xy is your nx2 matrix of [x,y] values.
[N,Xedges,Yedges] = histcounts2(xy(:,1), xy(:,2), 5);
% or use [N,Xedges,Yedges] = histcounts2(X,Y,Xedges,Yedges);
% Compute bin centers
Xcnt = Xedges(2:end) - abs(diff(Xedges(1:2))/2);
Ycnt = Yedges(2:end) - abs(diff(Yedges(1:2))/2);
figure()
contour(Xcnt,Ycnt, N)
% show bins
xlim = [min(Xedges),max(Xedges)];
ylim = [min(Yedges),max(Yedges)];
arrayfun(@(x)xline(x,'Color',[.8 .8 .8]),Xedges)
arrayfun(@(y)yline(y,'Color',[.8 .8 .8]),Yedges)
% colorbar
cb = colorbar();
ylabel(cb,'density')
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/335391/image.png)
Weitere Antworten (1)
KSSV
am 22 Jul. 2020
I would follow like below:
- You need to generate z values which are density values.
- I would fix a distance r and calculate the number of points within r for each point using rangesearch.
- Now you can use scatter to plot the density values.
- If your data is structured arrange the data and use contourf.
0 Kommentare
Siehe auch
Kategorien
Mehr zu Contour Plots finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!