Re:

[<HBB...@t-...>]

Petr Mikulik wrote:
> I propose to change the message
> 
> 	Notice: cannot contour non grid data!
> 
> into
> 
> 	Notice: Cannot contour non grid data. Please use "set dgrid3d".
> 
> Any objections?

Yes.  "set dgrid3d" is far from being the single, obvious solution to 
the problem.  A good portion of people having this problem simply don't 
know about grid-structured data files.  For them dgrid3d would be the 
wrong thing to do.

If you want to put a recommendation, make it a reference to (a to-be 
written node of) the manual.