Original(1.4GB file size): 9.263 Average points per feature Points:20346517 Features:2196329
Simplified (20cm) (1.2GB file size): 8.425 Average points per feature Points:18504036 Features:2196329 Simplified (40cm) (1.1GB file size): 8.07 Points:17741477 Features:2196329 For better statistics on how it affects file size for ontario (which is the biggest dataset by the way) The previous link I provided was for the 20cm simplification, I can provide a link to the 40cm simplification file if needed. I don't think simplifying about 50cm would be safe/smart as that would be getting into satellite imagery quality vs what the cities use (plane overhead gathering high-res imagery) On Sun, Jan 20, 2019 at 12:44 AM Nate Wessel <bike...@gmail.com> wrote: > I'm changing the subject line to try and retain some clarity for the > mailing list. > > James, thanks for the stats! I'm surprised this didn't remove more points. > > Steve, I mentioned earlier that 20cm is where I happened to draw the line > for the data we imported in Hamilton County, Ohio and I'm not totally sure > even that was ideal. A bit more than half of the buildings we've been > importing there have one (damned) extra node which I've been trying to > remove manually. I may have been a bit too conservative there, as I didn't > want to lose any part of the geometry. Sometimes there are tiny bay windows > and the like. > > I'm wondering if the scope of this data warrants some analysis of how > simplification (and perhaps data quality generally) varies geographically. > It seems quite likely that every municipality would have it's own quirks, > and we might want to treat some places differently. > > Best, > Nate Wessel > Jack of all trades, Master of Geography, PhD candidate in Urban Planning > NateWessel.com <http://natewessel.com> > > On 1/19/19 7:24 PM, OSM Volunteer stevea wrote: > > On Jan 19, 2019, at 3:47 PM, James <james2...@gmail.com> > <james2...@gmail.com> wrote: > Resending because these emails are getting over 40KB in size and talk list is > spazzing out: > Original: > 9.263 Average points per feature > Points:20346517 > Features:2196329 > > Simplified (20cm): 8.425 Average points per feature > Points:18504036 > Features:2196329 > > Choosing 20cm or higher or lower is where the "improvement?" line gets drawn. > > In round numbers of nodes, call this a "10% reduction." The question is, are > the results "improvement?" If so, it seems worth doing. (Only one person's > opinion, of course). > > Steve > > _______________________________________________ > Talk-ca mailing list > Talk-ca@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-ca > -- 外に遊びに行こう！
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