[Openstreetmap] Re: Naming segments using applet

Tom Carden tom at tom-carden.co.uk
Fri Dec 16 16:43:16 GMT 2005


> Hey folks,
>   This is going to get out-of-hand with the current db schema real
> quick.

Thanks for the words of warning. A few thoughts...

> The current schema is highly road/street paradigm dependant.

Great, because we're building street maps!

Sure, we're occasionally guilty of not-made-here syndrome, but equally
we're not precious about what already exists - if it's not working out,
and someone proposes a better solution, it will get junked (see our first
attempts at XML formats, the original over-architected key/value system,
the applet rewrite, etc.) - nobody here is afraid to rewrite things if
necessary.

>
> Before people start digitizing features other than roads/streets it
> would be advisable to move to a true GIS schema.  Either enable the GIS
> extensions to MySQL or switch to PostGIS before too much occurs or there
> will be a real mess.  "Tags" alone just won't cut it, please believe me.
> There are too many associated attributes for multi-feature GIS data to
> handle in this fashion.
>

BUT...

You aren't the first person to offer advice and plead for a move to a
"true GIS schema".  Thing is, most of us don't have an idea of what that
would look like, but OSM's code works *now* and does lots of things we're
interested in.  There are clear incremental paths of progression for OSM
to do lots more things we're interested in, and the biggest limit on us is
coding time, not bandwidth, resources, money, or what the database can
express.

> I've been a professional GIS technology consultant for over 8 years and
> have run into MANY instances exactly like this.  The resulting work to
> fix the problems was more than a little outrageous.
>

Can you point us in the direction of some of the MANY instances you're
thinking of?  And what were the lessons learned?  "Use PostGIS" isn't a
lesson.

Are you sure they were making wiki-style street maps?  We're not trying to
map the universe at 1:1 scale here, just map a few streets.  If canals and
stuff drop out of that for nearly-free, then all the better for waterway
enthusiasts, but I disagree that accomodating a few other 'street-like'
representations puts us on a slippery slope where the only solution is an
'industry standard' GIS database.  I think you misunderstand the scope and
focus of the project if you think the database situation is that bad.

Best,

Tom.






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