Warning: Contour not rendered for constant ZData

Question

Anyone can help me solve this error?

Warning: Contour not rendered for constant ZData
In contourf>parseargs at 467
In contourf at 64
In example at 298

Thanks in advance

Answer 1

A matrix with the same value everywhere (constant ZData) doesn't have any level change, so no contour can be drawn.

Example:

contourf([0 0 0 0; 0 0 0 0; 0 0 0 0; 0 0 0 0; 0 0 0 0])

It's no error, just a warning, as some people might wonder why it plots no contour.