Especially when the only imagery available is Landsat.... On Jun 30, 2017 2:18 PM, "Frank Steggink" <[email protected]> wrote:
> Hi Jochen, > > Maybe I'm not understanding it, but in the OSM inspector [1] I just see > one case of old style multipolygon, in Manitoba. Last week, when you posted > your original message, I just saw one case in New Brunswick. IIRC, it was a > park, not even from the Canvec import. > > In the OSM inspector other errors can be seen, but the most prevalent one > is "Touching rings". Maybe indeed a case of suboptimal mapping, but nothing > which seems urgent to me. > > Here is an example of a forest multipolygon, imported by me > (canvec_fsteggink). It is still version 1, but it has tags on the relation, > not on the rings (except for the quarries): [2] > This is from Canvec v7.0. IIRC, we started at v6.0, and the last version I > know of is v10.0. Maybe v6.0 had wrong tagging, but I'm not seeing any such > cases in the OSM inspector. > > So, I'd like to ask you to give a couple of examples where data imported > from Canvec is clearly wrong with regard to old style multipolygon tagging. > When we have clear examples, then it might be easier to come up with a plan > how to fix it. But so far, I see absolutely no reason why Canada stands out > in a negative way. Yes, we all acknowledge that Canvec data is suboptimal, > but as others already have pointed out, mapping everything by hand in > especially remote areas is nearly impossible. > > Regards, > > Frank > > [1] http://tools.geofabrik.de/osmi/?view=areas > [2] https://www.openstreetmap.org/relation/1481163/history > > On 30-06-2017 09:52, Jochen Topf wrote: > >> Hi! >> >> A week ago I wrote this email and nobody answered it yet. Does that >> mean that nobody feels responsible for the import that created this data >> and nobody here cares for this data? >> >> I see three ways forward: >> * We do nothing. The broken data stays in OSM. Not a good solution, >> because every user of the data has to work around this or handle the >> complaints. >> * The Canadian community steps up and fixes the data, automatically or >> manually. >> * We ask the Data Working Group to remove the broken import. >> >> Jochen >> >> On Thu, Jun 22, 2017 at 11:38:15AM +0200, Jochen Topf wrote: >> >>> Date: Thu, 22 Jun 2017 11:38:15 +0200 >>> From: Jochen Topf <[email protected]> >>> To: [email protected] >>> Subject: [Talk-ca] Multipolygon problems >>> >>> Hi! >>> >>> In the last days the OpenStreetMap Carto Style 4.0 is being deployed on >>> the OSMF tile servers. This new version of the style doesn't take >>> old-style multipolygons (where the tags are on the outer ways instead of >>> on the relation) into account any more. In a huge effort in the last >>> months we have converted all old-style multipolygons to the modern >>> tagging, so this is a good step! >>> >>> Unfortunately, as a side-effect of this change, many multipolygon >>> relations now appear wrong on the map. This is the case for multipolygon >>> relations that have the same tags on the relation as well as on (some of >>> the) outer or inner ways. This is *wrong* tagging, and needs to be >>> fixed. (Note that this always was wrong tagging, even before we >>> deprecated old-style multipolygons, but the way the software worked with >>> old-style multipolygons, this problem was not visible on the map. But >>> now it is.) >>> >>> Here is an example: http://www.openstreetmap.org/relation/1330741 . As >>> you can see (unless somebody fixes this :-) the clearing in the forest >>> that should just have grass, also has tree symbols on it. In many other >>> cases it is not this obvious, there are just islands in a river missing >>> or so. >>> >>> There are about 50,000 cases like this worldwide, forests, waterways, >>> all sorts of areas. But the worst problem is in Canada. There are about >>> 15,000 affected relations, most from the CanVec imports. >>> >>> First, we have to make sure that there are no further imports of broken >>> data. I hope the people who have done those imports (and might still >>> continue) are here on this mailing list. If not please make them aware >>> of this issue and/or put me in touch with them. Second, somebody needs >>> to clean up the broken data, either automatically or manually. 99% of >>> the data has not been changed since the import, so it might be feasible >>> to do an automatic cleanup, but somebody has to do this. Otherwise we'll >>> have to do a manual cleanup, through tools such as Maproulette and the >>> OSM Inspector. I am currently in the process of creating Maproulette >>> challenges for other areas of the planet, but will not do this for >>> Canada at this time. Lets discuss this here first. >>> >>> I can provide OSM data extracts, statistics, etc. if somebody wants to >>> look at the data. >>> >>> All of this is part of a larger effort to fix areas in OSM. See >>> http://area.jochentopf.com/ for more information. There is also a thread >>> on the talk mailinglist at >>> https://lists.openstreetmap.org/pipermail/talk/2017-June/078203.html >>> and this issue >>> https://github.com/osmlab/fixing-polygons-in-osm/issues/36 . >>> News of the effort are posted regularly to >>> https://github.com/osmlab/fixing-polygons-in-osm/issues/15 . >>> >>> Jochen >>> -- >>> Jochen Topf [email protected] https://www.jochentopf.com/ >>> +49-351-31778688 >>> >>> _______________________________________________ >>> Talk-ca mailing list >>> [email protected] >>> https://lists.openstreetmap.org/listinfo/talk-ca >>> >> > > > _______________________________________________ > Talk-ca mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-ca >
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