John,
The FGDC doc which has served as the source of our attribute definitions
for map projections provides the following information:
utm_zone_number -- the identifier for the UTM zone. It takes values
between 1 and 60 for the northern hemisphere, and between -60 and -1 for
the southern hemisphere.
For the geodetic model:
ellipsoid_name -- identification given to established representations of
the Earth's shape. The acceptable values are "Clarke 1866", "Geodetic
Reference System 80", and free text.
Allowing free text values means that the attribute can legally take any
text value. Presumably we would need to establish new names and references
for these quantities as user need dictates. For example we would need a
reference for the names "ED50" and "WGS84".
Are the attributes that describe the geodetic model legal for all map
projection names?
Should we specify that the default geodetic model is a sphere? Do we need
to provide a default of the spherical Earth radius?
Do these attributes meet your needs?
Brian
On Thu, Oct 23, 2003 at 09:00:10AM +0100, Jonathan Gregory wrote:
> Dear John
>
> Thanks for looking into this. If people want to use it with CF, I agree it
> should be supported. Since we want it to be self-describing as far as possible,
>
> > 1. If there is standard ellipsoid for each zone, it would be nice if
> > the ellipsoid parameter could be optional, since many may not know what
> > to put there.
> But we should say in the appendix what these defaults are.
>
> > 2. We probably want a controlled set of ellipsoid names (?)
> with appropriate links to further information which defines them.
>
> I'm afraid I don't know anything about this projection. As with other issues,
> I suggest it is up to those who want to use it, and therefore who know how it
> can/should be used, to propose the requirement.
>
> Best wishes
>
> Jonathan
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Received on Thu Oct 23 2003 - 12:50:47 BST
