[Openstreetmap] RoadMap map generator / editor
lester at lsces.co.uk
Mon Oct 17 11:14:28 BST 2005
Tom Carden wrote:
> The server should then merge all the points to a reined
> street segment.
> And that's the tough bit!
> I think the client/server separation you've made there is largely
> artificial. The real question is *how* to do it, not *where*. For OSM,
> sure, the merging would be done on the server, but for tasks where
> merging is made easier with context-specific knowledge, the client is
> better placed to do it.
The main problem here is providing a downloadable version that we can
use in car. The in-car package would then be able to mark tracks as
'new' or 'existing' and an update file can be created. Adding
information to existing data can also be included in the update and only
the update needs to be transferred back on-line.
> So the ideas I'm after are thoughts people have on merging an existing
> road with a GPS track. Or in OSM's case, an existing road with hundreds
> of GPS tracks of that road. When do we stop refining the shape? How do
> we take noise into account? How much priority do we give to the most
> recent data? ( e.g. if a new roundabout/intersection is added, and we
> have 100 GPS tracks which say there isn't one, but 1 GPS track for today
> which says there is - can that be automatically merged?)
> Those are the things I'm interested in. They're PhD-sized questions, I
The 'diff' process would allow for existing data to be made available so
history is maintained, but the current state could be shown. A new
roundabout is a permanent change, but some major roadworks re-route the
road and then return you to the original track months later. THAT is
more of a problem to manage, but should work with timestamps on data.
> Can you explain the wiki-like aspect of OpenStreetMap? What does it
> Basically every change made to OpenStreetMap is logged with a time
> stamp, and changes can be rolled back. Like the history function in
A nice database based system, with 'select first' ordered by date would
be ideal, but provided that there is a tidy method of defining the
update information, it should be possible to create a history package
that can step back through changes, while maintaining a simple 'current'
view. The real problem is creating a Jan04 view from the available data
without the data becoming totally bloated or it taking a week to create :(
L.S.Caine Electronic Services
Treasurer - Firebird Foundation Inc.
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