----- Original Message ----- From: "Richard Fairhurst" <[EMAIL PROTECTED]> To: "Talk Openstreetmap" <talk@openstreetmap.org> Sent: Wednesday, August 27, 2008 7:35 PM Subject: Re: [OSM-talk] Potlatch & duplicated node
> > David Groom wrote: > >> Whilst reviewing data I've noted recently a large number of duplicated >> nodes. These occur where one way joins another. > > http://trac.openstreetmap.org/ticket/915 > > In short, the issue is that Potlatch creates a node with an (internal) > negative ID. When the way is written to the server, the server assigns > the node a new ID, and this is sent back to Potlatch. Potlatch then > renumbers (say) node -5 to node 2876515. > > Unfortunately, this falls down if the server is running slowly (or the > user has an intermittent connection) and the user is working quickly. > If node -5 is shared by way A and way B, the user may upload way A, > and while the server is chewing on it, upload way B. Two separate > uploads, so two separate node IDs. > > It's the single biggest bug there is in Potlatch and the only reason I > haven't fixed it yet is because it's a Hard Problem. Probably the > solution is to "chain" uploads so B won't finish until A has; maybe > the solution is to have some type of server-side persistence so that B > can look up "user x, session y, node -5" and get 2876515. The easiest > answer to code would be simply for the upload of B to check if a node > already existed at that lat/long, and if so to use its id, but that's > just horrid. I'd say "patches welcome", but more in hope than > expectation. > Does thtis mean that in theory when creating a "T" junction it would be better to start from the existing way, insert a node, and then draw the new way "away" from the exisitng way, rather than to start a new way and move towards the exiting way and join on to that existing way? > >> I've managed to create a few myself, but have noted that many other >> users >> are doing the same. In each instance the relevant ways have >> "created by >> Potlatch" as tags. > > Although it's appropriate in this case, remember that created_by is > not a reliable indicator to what editor was used to carry out the > edit, for this reason: > > http://josm.openstreetmap.de/ticket/1047 > > and Potlatch's version number is in the created_by string for a > reason, please do quote it if you can. :) > > > On a general point, talk@ is not the Potlatch bugs reporting forum, > trac is, and my peculiar view of coding etiquette is that it's a > little more polite to contact the developer first rather than using a > public mailing list (and thank you very much to all those people who > do). I don't really mind too much, but experience shows people are > more likely to get defensive when problems are aired in public > initially, which can be counter-productive. > Fully appreciate and undersatnd that Richard, but felt it important to put mappers on notice that perhaps they should do a bit more checking of the data they have been working on. David > cheers > Richard > _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
