MATLAB Answers


Unwanted lines show up on surface plots

Asked by Al
on 26 Dec 2018
Latest activity Commented on by Walter Roberson
on 27 Dec 2018
See image below. Can anyone help me understand why the extra line shows up on the surface plot?
At first I thought it was a calulated point, however, it is not selectable with the data curser to determine the coordinates.
How can I get rid of these lines?


You have nan on your data.
on 26 Dec 2018
yes. i intentiomally have nan in the data to exclude certain solutions from being plotted.
i have if statements. if certain varibles are outside the constraints, then those get marked as nan so they are excluded from the plot and data output.
is there a way to continue to use the nan’s and get rid of the extra lines?
The dark lines are from the default 'edgecolor' 'Black' that surf uses. You can get rid of them by passing edgecolor none .
If you want the dark lines but not the apparent spike then you should probably investigate patch() and the various ways it has of specifying edge colour .
surf interpolates face color from four adjacent vertices. If any of the four is nan then the face is nan. But if you have two adjacent non-nan vertices then edge can be drawn between them. If they are surrounded by nan then no face will be drawn leading to edges drawn with no face.

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1 Answer

Answer by Image Analyst
on 26 Dec 2018

When you call surf() set 'edgelines' to 'none'
surf(x, y, z, 'EdgeLines', 'none');


Show 1 older comment
on 26 Dec 2018
i do like the black line around the edge of the data plot. will see what it does to it.
Right EdgeColor.
Seems like you don't want to set that to none if you like the lines. Looks like you just need to set an additional nan somewhere if you want to get rid of that isolated spike to nowhere. Of course that will be a very, very specific ad hoc fix just for that particular data set.
You might be able to use
zt = z;
zt(imclose(isnan(zt),ones(2,2))) = nan;
surf(x, y, zt, 'edgecolor', 'none')
except that this might not adjust the four corners correctly.

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