Upendra, Kyle, et al,
I proposed the use of an optional wkt attribute, for similar reasons to
those that you suggest, when I put together my submission for additional
CRS attributes to the CF standard. You can read some of the discussions
under CF trac tickets #9 and #18.
This particular attribute received a lukewarm reception at the time.
However, if you feel there is a stronger case now then by all means
submit another proposal to the CF trac site.
Of course, there's nothing to stop you adding a wkt attribute to your
netcdf files today. ESRI does just this. So long as the files are
CF-compliant in other respects then any additional attributes are
supplementary (I'm presuming CF-compliance is your goal).
Regards,
Phil
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu
> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Upendra Dadi
> Sent: 03 March 2010 20:42
> To: Kyle Shannon
> Cc: CF-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] equivalent of TOWGS84 in CF
>
> As I understand, scientists often use reference systems
> more complex than can be represented using the WKT. So it
> might not be good to fully depend on WKT, but having an
> optional attribute which can be used whenever possible might
> be a good idea.
>
> Upendra
>
> Kyle Shannon wrote:
> > I don't believe there are any such tags for TOWGS84. I
> would like to
> > see a more conformance or integration with OGC WKT as well. This
> > could take the form of spatial reference well known text or proj4
> > definitions. For the spheroid in cf, you have to specify
> earth_radius
> > and inverse_flattening or semi_major_axis and semi_minor_axis. I
> > think longitude_of_prime_meridian is in there too. The other
> > grid_mapping tags are for projected coordinate systems.
> >
> >
> >
> > -Kyle
> >
> >
> > On Wed, Mar 3, 2010 at 12:21 PM, Upendra Dadi
> <Upendra.Dadi at noaa.gov
> > <mailto:Upendra.Dadi at noaa.gov>> wrote:
> >
> > Hi,
> > I am new to CF convention. I am looking at how to incorporate
> > coordinate system information in the netcdf file.
> Referring to the
> > CF documentation, I found that there are parameters like
> > grid_mapping_name, semi_major_axis, longitude_of_prime_meridian,
> > etc to describe the coordinate system.But I haven't found any
> > attributes for specifying Bursa Wolf transformation parameters
> > (equivalent of TOWGS84 in WKT). Or am I missing something? These
> > parameters may be required when I am using data which
> is not based
> > on WGS 84 datum in order to be able to apply proper
> > transformation. Thanks.
> >
> > Upendra
> >
> >
> >
> >
> >
> >
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> >
> >
> >
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Received on Thu Mar 04 2010 - 02:49:26 GMT
