Hi! did you read those documents linked from http://area.jochentopf.com/ ?
https://github.com/osmlab/fixing-polygons-in-osm/blob/master/doc/background.md https://github.com/osmlab/fixing-polygons-in-osm/blob/master/doc/problems.md https://github.com/osmlab/fixing-polygons-in-osm/blob/master/doc/faq.md If there is something unclear after reading them, please ask, and I am happy to explain. Jochen On Fri, Mar 17, 2017 at 08:30:27AM -0400, john whelan wrote: > Date: Fri, 17 Mar 2017 08:30:27 -0400 > From: john whelan <jwhelan0...@gmail.com> > To: Jochen Topf <joc...@remote.org> > Cc: "hot@openstreetmap.org" <hot@openstreetmap.org>, Blake Girardot HOT/OSM > <blake.girar...@hotosm.org> > Subject: Re: [HOT] Broken (multi)polygon cleanup > > What isn't clear to me is just what you are trying to fix. The term means > nothing to me. I am correcting duplicate segments and unclosed ways which > appear to be part of your problem as I work. Perhaps someone can explain > what you are after in simpler terms because if we don't understand the > problem then trying to come up with ways to avoid it in the future isn't > going to happen. > > Thanks John > > On 17 March 2017 at 08:16, Jochen Topf <joc...@remote.org> wrote: > > > Hi! > > > > I am sure there are many other problems, but can we please keep to the > > issue at hand in this thread? I am not trying to solve all problems, I > > am trying to solve one particular set of problem related to > > (multi)polygons. > > > > And I didn't pick that particular problem at random. This is something > > that affects everybody. The short of it is: Due to upcoming software > > changes, some (multi)polygons that are rendered now will disappear from > > the map or look different in the future. Again, you can find all the > > details about the problems and of what we are trying to achieve at > > http://area.jochentopf.com/ . > > > > We are having great success working on these problems. You can see the > > stats at http://area.jochentopf.com/stats/ . This doesn't mean that the > > approach will be the best one for other problems, and it doesn't mean we > > can't do even better than we are doing until now with this problem. > > > > Btw: I am deliberately talking about "(multi)polygons". This is not > > something that only affects multipolygon relations, but all polygons, > > even the ones created from closed ways. They are simpler than mp > > relations, but that doesn't mean they can't have problems. > > > > Jochen > > > > On Thu, Mar 16, 2017 at 05:23:47PM -0400, john whelan wrote: > > > Date: Thu, 16 Mar 2017 17:23:47 -0400 > > > From: john whelan <jwhelan0...@gmail.com> > > > To: Jochen Topf <joc...@remote.org> > > > Cc: hot@openstreetmap.org, Blake Girardot HOT/OSM > > > <blake.girar...@hotosm.org> > > > Subject: Re: [HOT] Broken (multi)polygon cleanup > > > > > > This is similar to my pulling in Africa a country at a time and using > > JOSM > > > to check for errors. > > > > > > What I have noticed is one mapper will misstag then others will follow. > > So > > > sanitising the area or checking it for errors before the new HOT mappers > > > start would probably improve the overall data quality as they tend to > > > follow what is already mapped. > > > > > > Untagged ways by one mapper tend to cluster. I've seen a 100 buildings > > in > > > one small area by the same mapper left as area=yes. That's quick and > > easy > > > to fix. > > > > > > Recently I came across 42 highways left untagged by the same mapper in > > the > > > same area. The mapper had more than 2,000 edits so wasn't inexperienced. > > > > > > Crossing highways often I'll see a town where the highway residentials > > are > > > laid out in a grid but the junctions aren't nodes. > > > > > > Another nice recent one was a batch of settlements that had been tagged > > > highway=unclassified rather than landuse=residential. Searching for > > > highways above unclassified and crossing ways picked those out quite > > > quickly. > > > > > > These types of errors are handled more quickly directly in JOSM than > > > involving maproulette. > > > > > > Even the some other errors can be loaded up in the JOSM to-do plugin. > > > > > > I've been cleaning up in Nigeria for a while now. Making repeated passes > > > over the same areas over time. I'm seeing fewer errors so my suspicion > > is > > > the improved learnOSM, tutorials and simplifying what we ask mappers to > > map > > > is paying off. Validating new mappers work within 48 hours does pay off > > in > > > data quality terms. Giving feedback more than two weeks later is > > usually a > > > waste of time based on my own experience and Martin's report but I don't > > > think we have the validators to do the validation within the magic 24/48 > > > hours. > > > > > > Broken multipolyons do take a level of expertise to resolve. I usually > > > avoid them. However new mappers will fearlessly tread ahead and it is to > > > be expected they will break some. > > > > > > I don't think learnOSM goes into detail about them or about > > relationships. > > > Should they? That's another question. > > > > > > For some errors we need boots on the ground. Especially when it comes to > > > urban areas with limited access highways such as dual carriageways and a > > > highway approaching them can you turn in either direction? > > > > > > Often the most motivated people to fix the errors are the locals who will > > > be using the map. Trouble is we first have to get something in place > > that > > > is useful to get them motivated. > > > > > > So yes HOT maperthons do have a reputation of the blind leading the > > blind, > > > ie some are led by inexperienced mappers but we are putting effort into > > > reducing the number of errors. The training group has put together a > > very > > > good detailed set of instructions on how best to run a maperthon and if > > you > > > can identify a problem area HOT will listen and try to address the > > issues. > > > > > > Cheerio John > > > > > > On 16 Mar 2017 3:49 pm, "Jochen Topf" <joc...@remote.org> wrote: > > > > > > > Hi Blake, > > > > > > > > On Wed, Mar 15, 2017 at 05:29:04PM +0100, Blake Girardot HOT/OSM wrote: > > > > > Can you send me something that would help me see those 1600 examples > > > > > you found on OSM so I can see what might be going on and how to > > > > > improve things in HOT/MM workflow to reduce them? > > > > > > > > Those 1600 are some very specific errors I am currently looking at, but > > > > only have those on my local machine currently. But for the wider > > picture > > > > you can use the OSM Inspectors "area" view to see the scope of the > > problem. > > > > > > > > Just go to any place where HOT/MM was active. Here is an example: > > > > http://tools.geofabrik.de/osmi/?view=areas&lon=33.65927&; > > > > lat=-2.07600&zoom=8 > > > > > > > > My current workflow is as follows: I choose one particular well-defined > > > > problem and extract the data from OSM that shows this problem. Then I > > > > put the data into Maproulette and document the problem and how to fix > > > > it. Some problems are easier, some harder to fix. Mappers can choose > > > > what problems to work on based on their skill level. If somebody > > > > doesn't feel comfortable with one of the harder problems, there are > > > > simpler ones they can work on. I also have some more general > > > > descriptions for the experts who want to go exploring/fixing on their > > > > own. Once the challenges are done, I choose a new problem and start the > > > > process from the beginning. > > > > > > > > Here are the current challenges: http://area.jochentopf.com/ > > fixing.html > > > > > > > > Usually I am splitting up larger challenges into regions, for instance > > > > by continent or country. I could also do this by HOT activation area or > > > > so if that makes sense for HOT mappers. Splitting up, often makes the > > > > problems easier to fix, because problems inside an area are often very > > > > similar, but different to problems in other areas due to mapping > > > > priorities and methods. For instance, some regions have lots of > > problems > > > > with buildings, others with landuse areas, etc. Concentrating on one > > > > very well-defined problem at a time makes all this work simpler. > > > > > > > > Jochen > > > > -- > > > > Jochen Topf joc...@remote.org https://www.jochentopf.com/ > > > > +49-351-31778688 > > > > > > > > _______________________________________________ > > > > HOT mailing list > > > > HOT@openstreetmap.org > > > > https://lists.openstreetmap.org/listinfo/hot > > > > > > > > -- > > Jochen Topf joc...@remote.org https://www.jochentopf.com/ > > +49-351-31778688 > > -- Jochen Topf joc...@remote.org https://www.jochentopf.com/ +49-351-31778688 _______________________________________________ HOT mailing list HOT@openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
