[CF-metadata] CF-1.0-beta5: curvilinear bounds "contiguous"attribute

[jonathan.gregory at metoffice.com]

Dear All

A further comment re contiguous: Multidimensional coordinate variables must be
auxiliary coordinate variables. Boundary variables like (m,n,npoly) must be
boundary variables corresponding to auxiliary coordinate variables.

Is it not therefore the case that there must also be ordinary 1D coordinate
variables, which should have boundary variables too? If so, can't
contiguousness be determined from the 1D variables? This surely must give the
same answer as working it out from the 2D variables. If two points are
coincident in one coordinate system, it would be a strange transformation
that mapped them to different points in another system.

The difficult cases for contiguousness are the ones where the cells aren't
arranged in a rectilinear array in any coordinate system, I think. Maybe I
am missing something obvious here. Please help me out of my misunderstanding
if so.

Thanks

Jonathan