Hi I've just signed up to the dev mailing list, and hopefully i'll catch up by reading the archives. For now though I have a question and please don't follow up with insults if you see the names Microsoft or SQL Server :P
I'm trying to render coastlines in an application that I am building. The concept is simple: find the lines, and join them end on end until you get an area. Now my problem is with OGC standards. I'm using Sql Server 2008 *ducks for cover* and more specifically the new Sql Server Spatial types (Geography and Geometry). Sql Server 2008 seems to be pretty strict with OGC standards, and I am but a beginner when it comes to OGC standards. The problem i'm having is with some coastlines in OSM that double back on themselves. Like this one: This way http://www.openstreetmap.org/browse/way/13858554 doubles back on itself with this node http://www.openstreetmap.org/browse/node/130020792 having the same latitude as this consecutive node http://www.openstreetmap.org/browse/node/130020793. I think this is the reason for the way being invalid in Sql Server's eyes. The MS folks have included the MakeValid() function which "corrects" the way to comply with OGC standards, but this changes the latitude and longitude of every point in the line ever so slightly, and that's not desirable if you are matching ways end on end. I can use the Node Ids to match them, but the bigger issue is that my data is "invalid" and I can't use other spatial methods on it. I have 4 questions: 1. Is this doubling back really an OGC restriction? It makes sense that these ways don't double back because it doesn't serve any purpose for a coastline (or for any line, you would expect even a path that doubles back to be at least some distance apart, or simply labeled two way). 2. If this is a problem, is it something that will be fixed in the editors / the API? 3. Is there anyone else here with experience with SQL Server 2008 Spatial and OSM that might have some tips on dealing with all these ways? 4. Does PostGIS have these types of issues? I'm thinking that the only way for me to deal with this is to correct the data in OSM (if it's clearly incorrect) or in my database once imported (if there's no other solution). Thoughts? _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
