plot contour line of three variable ?
显示 更早的评论
Hi I have thistext file ( please see attached )with 3 columns ( lat, lon and depth ) I want to plot a contour map of the water depth as a function of lat and lon. I used the following code contour (lat,lon,depth) where I extracted lat, lon, and depth separately but I get this error "Z must be at least a 2x2 matrix."
any help ? thanks
回答（2 个）
Star Strider
2017-12-20
编辑：Star Strider
2017-12-20
If the file is very large, probably the easiest way to see if your data are gridded (such that the ‘x’ and ‘y’ values repeat in a specific, regular pattern) is to plot your vectors using the stem3 function. If they appear to be regularly-spaced, you can use the reshape function to form them into matrices. Then you can use your matrices with contour.
If they are not gridded, you will have to interpolate them to be gridded matrices. See the griddata (link) function and its friends to do that.
EDIT —
If ‘M’ is your (Nx3) matrix:
x = linspace(min(M(:,1)), max(M(:,1)), size(M,1)+1);
y = linspace(min(M(:,2)), max(M(:,2)), size(M,1)+1);
[X,Y] = meshgrid(x, y);
Z = griddata(M(:,1), M(:,2), M(:,3), X, Y);
figure(1)
contourf(X, Y, Z)
axis equal
grid
Experiment to get the result you want.
类别
在 帮助中心 和 File Exchange 中查找有关 Contour Plots 的更多信息
2017-12-20
2018-3-15
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
