Mesh function creates extra face joining first and final data points

Hi,

I have data for three variables and I have use mesh function to draw a 3d chart.

I have used the following code,

"

[X,Y]=meshgrid(vx,vz)

Z=griddata(vx,vz,astrain,X,Y)

mesh(X,Y,Z)

"

when I graph the chart, I get an extra face with joining the first and last data point

How can I avoid this?

PS: I'm new to Matlab.

Answer 1

[Star Strider]

Try something like this —

vxv = linspace(min(vx), max(vx), numel(vx));
vzv = linspace(min(vz), max(vz), numel(vz));
[X,Y]=meshgrid(vxv,vzv)
Z=griddata(vx,vz,astrain,X,Y)

figure
mesh(X,Y,Z)
grid on

The problem is likely in the original ‘vx’ and ‘vz’ vectors. Creating different version of them to create the interpolation matrices may solve this.

I do not have the necessary data to test this, so I am posting it as UNTESTED CODE.

.

[Rashiga Walallawita Walallawita Kankanamge]

@Star Strider this code worked! Many thanks.

Could you kindly explain why did you use this code?

vxv = linspace(min(vx), max(vx), numel(vx));

[Star Strider]

As always, my pleasure!

Sure!

The original vectors were apparently not monotonically-increasing, causing the problem that your reported.

My code creates a monotonically-increasing vector spanning the range of each original vector (and with the same number of elements, although that is simply for convenience, since the third argument to linspace can be anything reasonable), avoiding the problems of it not being monotonically increasing, that is usually the cause of ‘wrap-around’ problems like those you reported. It then creates appropriate interpolation matrices with the same properties.