Hi, Listers.
I have a question of coordinate system after going through available
documents. Correct me if I am wrong.
Accodring to the CF-Convnetions, parameters such as projection approaches
(eg. Lambert_Conformal_projection) are specified. However, I find no
information about the DATUM. Although it is assumed to be WGS84, there is
possiblity for data in other datum such as Bessel-1841 specified in RT90.
My question is, why not make the DATUM as a standard parameter? With all the
effort being made by ncML, the inconsistency with other correctly
geo-referencing dataset is still possible due to the lack of DATUM
parameter. Am i naive or missing/misunderstanding something on the issue?
ps. some ideas about ncML and netCDF, please correct me if I am wrong One
crucial point is that the ncML is the metadata of netCDF files. Information
in ncML is orginated from netCDF. It's true that users can edit ncML to make
it more complete, however, it still depends on the header of netCDF. Suppose,
a user trying to create a data in his national coordinate system (eg. RT90)
using CF-Conventions. The user specified the projections and relevant
parameters. It seems fine at first. However, when the data is distributed
and people who download the data can't be able to know that the datum is
Bessel-1841 which specified in RT90. The system would transfer the
coordinate system using WGS84 as datum. That, eventually, would lead to
inconsistency with other data.
Cheers
Shawn
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Received on Tue Feb 06 2007 - 12:04:41 GMT
