[CF-metadata] X and Y projection coordinate (center vs corner)

[Jonathan Gregory]

Dear Thomas

I agree with you that for many purposes cells are not required (e.g. you don't
need them for doing contour plots). I also agree that in practice (again, such
as making contour plots) you assume the data applies at points, even when it
is extensive in space. In a sense, it is somewhat undefined for model data
whether it is point or cell; in a model, space is quantised so the distinction
is blurred.

You are right, I am not enthusiastic about making a formal relation between
the vertices and the gridpoints! However, I would not be against including a
statement in the convention that the gridpoint should typically be positioned
within the cell, rather than on the boundaries, if there is no good reason
otherwise. Maybe we do say something like that, but I can't remember where.

I agree that we should have a debate. Others' views are welcome.

Best wishes

Jonathan