[Gdal-dev] A Question of Coordinate Storage

[David M. Baker]

All,

 

Though this question is not specific to GDAL, OGR or FWTools, I believe some
of the most knowledgeable people of the subject are on this mailing list and
hope you will allow me to ask.

 

At my company, there is an ongoing debate as to the best coordinate system
to store cooperate spatial data in.  The debate is mainly between the
Geoscience department and the GIS department.  The vast majority of the data
the Geo's use comes from public sources that are in geographic lat/lon in
NAD27.  This data is then reprojected for mapping and display in various
coordinate systems, state plane and UTM (zones 12 - 18, but mostly in 13, 14
and 15).  The GIS guys supply many layers to the Geo's for display.  They
are currently upgrading from ArcSDE 9.1 to 9.2, and in the process are
converting all their coordinates for storage in UTM zone 14.  GIS made the
comment that this is a much more accurate way to store the data, that
geographic coordinates are less precise, though, their main reason for
storing the data in a projected system is to avoid having to do any
coordinate conversion on the fly when displaying the data on corporate web
maps.  The layers supplied to the Geo's will need to be reprojected if their
current map projections are not UTM Zone 14.

 

The question: is it wise to store coordinates that cover such a wide area in
a single projected coordinate system, or would it be better to store them in
some geographic coordinate system, e.g., NAD83 or WGS84?  And if this not
the best way (UTM14), why?  What are the pitfalls?  Is it really more
accurate, or precise to store data in a Cartesian coordinates and suffer the
conversion to a different projection as needed?

 

Thanks,

David

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20071007/52a2497c/attachment.html