Why do the contour functions not return a contour at the minimum value of my Z data?

I have a set of data for which I am trying to create a set of contours. I specify the minimum value of my Z data as one of the contour levels to create. However, a contour is not created at that level:

contourc(1:3,1:3,[1 0 1;0 1 0;1 0 1],[0 0])

 ans =

    Empty matrix: 2-by-0

If I specify the maximum value of the Z data as a contour level, it is created. Why isn't a contour produced at the minimum value?

Answer 1

[MathWorks Support Team]

This bug has been fixed in Release 14 Service Pack 2 (R14SP2). For previous releases, please read below for any possible workarounds:

This bug has been fixed for Release 14 (R14). For previous releases, please read below for any possible workarounds:

As a workaround, you can add EPS to the contour level, so it isn't exactly equal to the minimum value. For example:

contourc(1:3,1:3,[1 0 1;0 1 0;1 0 1],([0 0] + eps))