Hi Folks
Speaking as a person who has done budget studies in the past, I think exact
comparisons are the way to go ... not only in the variables, but in their
coordinates ...
> What would be a "contrived" example where 1E-5 would not work ? We are
> not trying to preserve numerical results in the face of complex
> algorthims, just trying to answer the question if the bounds are
> continuous.
Ok, if my cells are in the mesosphere of an atmospheric model, particularly
one that includes the troposphere, then the cells are going to be pretty
deep, possibly a couple of orders of magnitude in difference in pressure
coordinates .... if I then couple on a thermospheric model, and I'm stupid
enough to carry on using pressure as the vertical coordinate, then my cells
will become many orders of magnitude apart ... I can imagine failing the
above equality test in that situation ... even when the cells are contiguous
... other coordinate systems at that altitude may have even more problems.
As a personal aside:
>Someone has tried to create a CF netcdf file and bungled it, by not
>getting the coordinate bounds correct. So I am going to use NcML to fix
>the problem, by adding some of the values in "by hand".
I know you are using ncml to generate catalogues, and so I can see the
incentive for *fixing* the ncml associated with files , however, if folk are
using the ncml to instantiate code for doing things with the data based on
the ncml, I think it would be dangerous to rely on "by-hand-fixes" in
the markup that are not representative of the actual data files ...
.... having said that, I know about real users and what they do ...
Cheers,
Bryan
--
Bryan Lawrence, Head NCAS/British Atmospheric Data Centre
web: www.badc.nerc.ac.uk phone: +44 1235 445012
CLRC: Rutherford Appleton Laboratory, Chilton, Didcot, OX110QX, UK
Received on Fri May 23 2003 - 00:04:59 BST
