[Loadstone] Id Dispensability

Cathomas Jürg Juerg.Cathomas at sbv-fsa.ch
Wed Feb 28 13:08:51 GMT 2007


;someone renames a point, the name changes and without an
;id, there is no way to detect the rename.  
i wonder why you do not use the id for checkpoint files as well?
now, if you update a points coordinates, you'll loose the checkpoint definition for this point.



-----Ursprüngliche Nachricht-----
Von: loadstone-bounces at loadstone-gps.com [mailto:loadstone-bounces at loadstone-gps.com] Im Auftrag von Shane
Gesendet: Dienstag, 27. Februar 2007 17:55
An: General discussion pertaining to the Loadstone GPS program
Betreff: Re: [Loadstone] Id Dispensability

On Tue, Feb 27, 2007 at 12:45:40PM +0100, Przemys?aw Rogalski wrote:
> Is such kind of data really necessary in POI files?
> Wouldn't it be enough (and more practical) for Loadstone
> to differentiate (esp. duplicated) points just by their
> names and coordinates?

The id needs to be there and the various converters do
their best to generate unique IDs.  However, if you are
generating your own files from other sources, you've gotta
take care of ids under your userid.  If the various sources
out there for which the converters were written would allow
redistribution of their data, this would be less of an
issue as the data could be imported once and made available
to everyone.  Therefore, I would suggest contacting data
sources to that effect if it is practical to do so.

The reason we cannot have a primary key on
name,latitude,longitude is all of that data is dynamic.  If
someone renames a point, the name changes and without an
id, there is no way to detect the rename.  The coordinates
can also change via the update point feature and there is
no reason why all of this data couldn't change before an
upload to the PSE.  The id is rather like an anchor and no
matter what you do with a point, the id will never change.

Hth,
Shane

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