On Sun, Jan 17, 2010 at 20:29, Karl Palsson <[email protected]> wrote: > Ævar Arnfjörð Bjarmason wrote: >> Tom að mestu rakið vegi bæði frá egin GPS ferlum og u.þ.b. 30 annara >> sem hafa sent honum gögn en hann segir að um 95% af kortinu sé búið >> til svona, 5% er teiknað eftir lokuðum kortum (LMÍ kortum geri ég ráð >> fyrir), ár, vötn, jöklar og strandlengjan eru svo teiknuð eftir Google >> Satellite myndum. > > How did you go about excluding the 5% that were copied from other maps? You > do > know that importing this has totally corrupted any claim OSM might have on > being > completely clean data?
5% of Tom's source dataset is partially derived from Google Maps / LMÍ but none of what just got imported on OpenStreetMap. What the ourFootPrints import imported was a subset of the ourfootprints.de dataset, it was just the GPX traced ways & none of the Google Satellite traced waterways, POIs or various other things that were either unfit for importing or we'll possibly do in the future. > Further, what possibly motivated you to import this over reykjavik? We now > have > a great big pile of vomit, with no real known source or age, whose only real > qualification is that a bunch of Germans made it before OSM existed. Good for > them. When you do any sort of data import into an area with existing data you're going to have conflicts. There are a few ways to deal with that: * Delete all the existing data & Import the new one, obviously not applicable here but this was done e.g. in Gaza * Try to automatically or manually detect conflicts before uploading. This was done for the Corine import & requires a lot of programming / debugging / testing work or manual labour by a limited group beforehand. * Import the data on top of the existing data & clean it up later I went with the last option after it became clear that most of the users doing regular edits (who replied on the list) were willing to help clean it up afterwards. The whole import is only around 8000 ways which isn't too big for such manual cleanup work. I'm sorry for any inconvenience this has caused and in the areas such as Reykjavík where this import affects most users (especially those using Potlatch such as yourself) I'll try to cleanup the data very soon. I probably would have done so already for the capital area except I've been fixing up the import slightly by deleting source=* tags on all the nodes I imported. Most of the OFP data in Reykjavík and its surroundings will be deleted, except some residential ways which haven't yet been covered by us (like some in Kópavogur) and a few tracks. > While this surely has some very positive outcomes in unmapped areas, in other > areas we now just have a mess that someone has to go out and _resurvey_ just > to > try and work out which one is right. How is this a bad thing? Once we're done with the cleanup we'll have data in areas where we had none before. Sure that data may be out of date or incomplete but it's still *some* data instead of none at all. We may need to treat ourfootprints data as implicitly needing confirmation or resurveying of course, but in the meantime we at least have something. > Further, large chunks of the OFP import in reykjavik isn't even _semantically_ > correct, let alone geographically correct. Roads that overlay, but don't > intersect, Roads drawn as straight lines, which may have been straight on > original city plans, but clearly are not when you stand on the street, roads > or > connections that don't exist anymore. Yes a lot of the OFP roads don't connect with each other (although some do). Errors like that can be easily fixed with the validator when the data is imported. As for the accuracy see the point above. > In some other parts of the country, this was _possibly_ a good idea, but I'm > sorry, I really think this was a bad idea to import the whole lot. Out in the country it was definitely a good idea. The import greatly expands our coverage of the national highway system & various offroad tracks. The quality of those ways is on par with or even surpassing our own existing ways. _______________________________________________ Talk-is mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-is
