[Openstreetmap] Re: Openstreetmap Digest, Vol 12, Issue 12

[Chris Holmes]

> SteveC wrote:
> > * @ 13/08/05 03:03:07 PM f_mohr at yahoo.de wrote:
> >
> >>SteveC wrote:
> >>
> >>>Hi,
> >>>
> >>>We're trying to rapidly ditch the xml-rpc in favour of a restful
> api.
> >>>See: http://www.openstreetmap.org/wiki/index.php/REST
> >>
> >>i just had a look at the page
> >>shouldn't we use a subset of GML instead of extending gpx for the
> REST
> >>interface?
> >
> >
> > Fair point, though I'm not really bothered, it's all xml in the
> end.
> > What are the advantages of GML?
> >
> > Havn't had to extend gpx yet, either.
> >
> > have fun,
> >
> > SteveC steve at fractalus.com http://www.fractalus.com/steve/
> >
> >
>
> lets start with the concept
> - GPX was designed to exchange GPS data
> - GML was designed for "general purpose" geographic informations.
>
> GPX defines
> - waypoints
> - routes - list of points
> - tracks - list of track segments
> - track segment - list of points
> GPX doesn't define
> - areas
> - connection between elements
>
> i think we need to define the following relations:
> - street consists of several segments
> - a segment might belong to several streets
> - a street belongs to a administrative area
> - a administrative area belongs to a higher administrative area
>
> i've uploaded a few tcm drawings for this on
> http://www.openstreetmap.org/wiki/index.php/User:FrankM

I think you're on the right track with thoughts of doing GML.  Indeed
we've started an introduction to WFS concepts with one of the goals
being to help convince OSM to go with WFS (and more generically
providing a good intro to the good OGC specs, since reading them
yourself sucks).  Was hoping to finish it up, but both David and I are
pretty busy over the next bit, so may as well post the start, see:
http://udig.refractions.net:8080/confluence/display/GOWS/WFS

WFS _is_ a restful system of obtaining and updating geographic
information, indeed when I looked at the proposal for the new OSM
interface I found it very similar to WFS, much more so than the xml-rpc
one.  WFS is more generic than just street data, and what OSM's value
would be is defining a well known data model for publically annotated
street data.  You can keep your model simple, GML is more a
meta-language with elements you can reuse.  Also with WFS you aren't
actually tied to GML, if an RDF-GML language emerged, you could easily
swap over to that by just adding a new output format.

I think the segment and nodes belonging to more than one street are very
important, so you build a topology network, noded streets on top of
which you can do routing information.

The big advantage of going with GML and WFS is that they are standard,
which means there are a growing number of standards supporting them. 
Udig is a desktop client that fully supports WFS, including
transactions.  I think it will even handle security, which you could
use to do attributions, and then on the WFS backend you can persist
version information and the like.  Ok, at some point I will do a full
write-up on all the advantages, but it's basically 1) you don't have to
write everything yourself, you can focus on the value added of OSM, and
2) you will integrate much more easily with other data.

best regards,

Chris

>
> frank
>
>
>
>
>
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> ------------------------------
>
> Message: 4
> Date: Sat, 13 Aug 2005 20:27:19 +0100
> From: nick at hogweed.org
> Subject: Re: [Openstreetmap] API feature request
> To: openstreetmap at vr.ucl.ac.uk
> Message-ID: <200508132027.19919.nick at hogweed.org>
> Content-Type: text/plain;  charset="iso-8859-1"
>
> On Saturday 13 August 2005 15:03, Frank Mohr wrote:
> > SteveC wrote:
> > > Hi,
> > >
> > > We're trying to rapidly ditch the xml-rpc in favour of a restful
> api.
> > > See: http://www.openstreetmap.org/wiki/index.php/REST
> >
> > i just had a look at the page
> > shouldn't we use a subset of GML instead of extending gpx for the
> REST
> > interface?
> >
>
> My personal preferences are for (an extension of) GPX as it's light
> and
> concise.
>
> Nick
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sat, 13 Aug 2005 22:06:07 +0100
> From: nick at hogweed.org
> Subject: Re: [Openstreetmap] Re: update - open letter to google
> To: openstreetmap at vr.ucl.ac.uk
> Message-ID: <200508132206.07439.nick at hogweed.org>
> Content-Type: text/plain;  charset="iso-8859-1"
>
>
> > Actually, that's why I was having a play around with the OSM XMLRPC
> > interface the other weekend. I'd like to have a go at producing a
> > viewer client with Flash/Ming, which (despite the flaws of SWF as a
> > platform) is probably the quickest way to get Google Maps levels of
> > slickness.
>
> Richard,
>
> Have you thought of experimenting with AJAX and/or SVG? That's what
> I'm doing
> at the moment.
>
> Nick
>
>
>
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>
> End of Openstreetmap Digest, Vol 12, Issue 12
> *********************************************
>




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