it does if you saw my analysis of building(polygon count) remains the same also visually inspected a few and there was preservation of them
On Sat., Jan. 26, 2019, 11:43 a.m. Nate Wessel <bike...@gmail.com wrote: > Does that preserve topology between buildings that share nodes? > Nate Wessel > Jack of all trades, Master of Geography, PhD candidate in Urban Planning > NateWessel.com <http://natewessel.com> > > On 1/26/19 11:31 AM, James wrote: > > no need for scripts, qgis does this fine via the Vector menu -> Geometry > tools -> Simplify Geometries utility. I simplified it to 20cm with the , > but I think 40cm is too aggressive. > > I already have scripts to compile it into the dataformat needed to be > served. > > On Sat., Jan. 26, 2019, 11:16 a.m. Nate Wessel <bike...@gmail.com wrote: > >> Hi all, >> >> The wiki page is indeed looking a whole lot better right now - my thanks >> and congrats to everyone who contributed! There is a still a ways to go, >> but we seem to be getting there quickly. >> >> I'll echo John in saying that I would appreciate hearing from some of the >> other people who chimed in to express their doubts about the import. For my >> part, I'm not satisfied yet - no surprise, I'm sure ;-). I'm thrilled that >> we're talking and working together in the open, and that addresses the >> biggest concern I had with the import. >> >> These are the big issues I see remaining: >> >> 1. *Validation*: Ideally I'd like to see a good chunk (more than half) >> of the data that has been imported already validated by another user before >> we proceed with importing more data. Validation is part of the import plan, >> so the import isn't done until validation is done anyway. My hope is that >> this will flag any issues that we can fix before moving forward, and give >> people time to chime in on the import plan who maybe haven't already. I >> don't want to see everything imported and only then do we start >> systematically checking the quality of our work, if ever. If no one wants >> to do it now, no one is going to want to do it later either, and that >> doesn't bode well. >> >> 2. *Simplification*: James' analysis showed that simplification could >> save several hundred megabytes (and probably more) in Ontario alone. This >> is totally worth doing, but we have to document the process and be very >> careful not to lose valuable data. I believe there was also a concern >> raised about orthogonal buildings being not quite orthogonal - this is >> something that we should handle at the same time, again, very carefully. We >> certainly don't want to coerce every building into right angles. With >> respect to James, I'm not sure this is something that can be done with a >> few clicks in QGIS. I would be willing to develop a script to handle this, >> but it would take me about a week or two to find the time to do this >> properly. We would need to simultaneously A) simplify straight lines B) >> orthogonalize where possible and C) preserve topology between connected >> buildings. This is not impossible, it just takes time and care to do >> correctly. >> >> 3. *Speed and Size*: To John's point, it seems like people certainly are >> not sticking to the areas they know, unless they get around a whole hell of >> a lot more than I do, and yes this is a problem. The whole Toronto region >> was basically imported by two people: DannyMcD seems to have done the >> entire west side of the region (hundreds of square kilometers) while >> zzptichka imported the entire east side of the region (again a truly >> massive area), both in the matter of a week or two. They only stopped in >> the middle where there were more buildings already and things got a bit >> more difficult. The middle is where I live, and when I saw that wave of >> buildings coming, I sounded the alarms. >> This is way too fast - no one person should be able to import the GTA in >> a couple weeks. A big part of the problem, IMO is that the task squares are >> much too large, and allow/require a user to import huge areas at once. At >> the least, some of the task squares in central Toronto are impossibly >> large, including hundreds or thousands of buildings already mapped in OSM. >> Conflation on these, if done properly would take the better part of a day, >> and people are likely to get sloppy. >> I would like to see the task squares dramatically reduced in size as a >> way of slowing people down, helping them stick to areas they know well, and >> keeping them focused on data quality over quantity. This would also make >> the process much more accessible to local mappers who don't already have >> tons of experience importing. >> >> 4. *Conflation*: I don't think the current conflation plan is >> adequate(ly documented). In practice, what people are actually doing may be >> fine, but I really want to see some better thought on how to handle >> existing buildings. Right now the wiki says for example "*Before merging >> buildings data switch to OSM layer and see if there are any clusters of >> buildings without any meaningful tags you can delete to save time when >> merging*." >> With respect to whoever wrote this, this approach seems to value time >> over data integrity and I just don't think that's how OSM should operate. >> We need to be more careful with the existing data, and we need to show that >> care with clear and acceptable guidelines for handling the data that >> countless people have already spent their time contributing. We don't do >> OSM any favours by carelessly deleting and replacing data. Help convince me >> that this isn't what's happening. >> >> Until some effort has been made to address these concerns, I will >> continue to oppose this import moving forward. And to be clear, I don't >> want to oppose this import - I have too much else I should be focusing on. >> I just don't want to see another shoddy import in Toronto (or elsewhere). >> >> Best, >> Nate Wessel >> Jack of all trades, Master of Geography, PhD candidate in Urban Planning >> NateWessel.com <http://natewessel.com> >> >> On 1/26/19 8:49 AM, john whelan wrote: >> >> I'm not certain how this addresses the concerns raised by Andrew Lester >> and >> >> Pierre Béland, and I seem to recall one other person who expressed >> concerns. >> >> I think it is important that their concerns are addressed. >> >> Perhaps they would be kind enough to comment on whether or not this >> approach addresses their concerns. >> >> Do we have a concern that some mappers have been importing buildings >> further than say twenty kilometers from where they live? >> >> >> Have you found volunteers of local mappers in >> Alberta >> British Columbia >> Manitoba >> New Brunswick >> Newfoundland and Labrador >> Northwest Territories >> Nova Scotia >> Nunavut >> Ontario >> Prince Edward Island >> Quebec >> Saskatchewan >> Yukon >> >> Who will be willing to oversee the import in each province? >> >> Does this mean the smaller provinces may not see any data? >> >> How will you handle cities of say 80,000 population in a smaller province >> who have an interest in seeing their buildings available but have no idea >> on how to contact the provincial group? >> >> >> >> If we go back to earlier times it was a suggestion in talk-ca that we use >> the single import approach and it was mentioned at the time there didn't >> seem to be a list of local mapper groups in Canada. >> >> I'm not saying the approach of a single import as far as the import list >> and talk-ca followed by a procedure of locally organised mappers bringing >> in the data is wrong I'm just trying to ensure the project moves forward >> and we are in agreement. >> >> Thanks >> >> Cheerio John >> >> On Sat, 26 Jan 2019 at 00:17, OSM Volunteer stevea < >> stevea...@softworkers.com> wrote: >> >>> Thanks to some good old-fashioned OSM collaboration, both the >>> https://wiki.osm.org/wiki/Canada_Building_Import and >>> https://wiki.osm.org/wiki/WikiProject_Canada/Building_Canada_2020#NEWS.2C_January_2019 >>> have been updated. (The latter points to the former). >>> >>> In short, it says there are now step-by-steps to begin an import for a >>> particular province, and that as the steps get fine-tuned (they look good, >>> but might get minor improvements), building a community of at least one or >>> two mappers in each of the provinces with data available, the Tasking >>> Manager can and will lift the "On Hold" or "Stopped" status. >>> >>> Nice going, Canada! >>> >>> See you later, >>> >>> SteveA >>> California >>> _______________________________________________ >>> Talk-ca mailing list >>> Talk-ca@openstreetmap.org >>> https://lists.openstreetmap.org/listinfo/talk-ca >>> >> >> _______________________________________________ >> Talk-ca mailing >> listTalk-ca@openstreetmap.orghttps://lists.openstreetmap.org/listinfo/talk-ca >> >> _______________________________________________ >> Talk-ca mailing list >> Talk-ca@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/talk-ca >> > _______________________________________________ > Talk-ca mailing list > Talk-ca@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-ca >
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