[Openstreetmap-dev] Streets in GPX

SteveC steve at asklater.com
Fri Sep 23 12:42:34 BST 2005


Before I dive in, my take on streets:

Street segments connect two nodes, and have an implicit direction in
which node is first and which is last.

By making streets a list of segments you can do cool things like have
non-connected streets. I'm desperately trying to think of an example
where this is useful, but I'm sure that there must be one.

The other thing is that segments can belong to multiple streets. So
multiple segments can belong to 'baker street' but they can also belong
to 'Bus number 13's route'.

As for representation in xml... I'm not sure how worried I am. Any
effort I put in will be obliterated by gzip-encoding by HTTP.

> Is GPX really sensible to use as the map exchange format?  I suspect
> other formats are better.  For example Shapefile, GML or any of the
> other formats designed to contain maps.

If it's XML, I don't care how it's represented. It's easy enough to
tranform it or modify all the code to use some other schema.

* @ 23/09/05 12:03:16 AM nick at hogweed.org wrote:
> Of course OSM could make up its own XML format for representing maps....

Arrggghhh! :-)

> in my opinion the current representation for nodes in data transfers
> might give some problems with floating point comparisons
> (the old XMLRPC interface gives every node a unique nodeid,
> while the GPX interface represents nodes as float LAT/LON)

No it doesn't, the nodeid is in there.

If you've just seen lat/lon without the name (shortly to be number) tag
thats a bug.

> Maybe, indeed: use GPX for the moment, but in the longer term, it would be 
> good to see a simple, clear mapping format that's as accessible as XHTML. It 

Sounds good to me

have fun,

SteveC steve at asklater.com http://www.asklater.com/steve/




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