FYI: Highly useful note on lat - long, position, and relationship to datums

The attached document was provided by Roger Lott., retired Chief Surveyor 
of BP Oil and currently chair of the OGP [epsg] Geodesy Subcommittee. Roger also 
participates in and contributes to the Coordinate Reference System (CRS) 
work  in the OGC and in ISO TC 211. I think it is a great document that 
explains the relationship between a lat-long coordinate and the associated datum 
- and what happens if datums are not properly specified. The reason for 
providing this document is we (in the OGC) are always encountering individuals 
that have heard the term Latitude-Longitude but are not necessarily aware of 
what using the term really means and why standards organziations are so picky 
about how the CRS information needs to be properly expressed.

 

And if anyone wants to dig more deeply:

 

Datums and Map Projections: For Remote Sensing, GIS and Surveying, 
Second Edition 
Jonathan IIiffe and Roger 
Lott
Published: 2008-02-15, Taylor 
and Francis
ISBN: 9781420070415 

 

Regards

 

Carl Reed, PhD
CTO and Executive Director Specification 
Program
OGC

 

The OGC: Helping the World to Communicate Geographically

 

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Latitude and longitude coordinates are not unique.doc