Adding in step 5 sounds just fine. I didn't know about the lack of waterway=river in NHN, since I had already Yahoo traced all the major rivers in my area long before the NHN import had even started, and only had to bring in riverbanks from Canvec :)
I'd say I'm in agreement now. Adam On Tue, Feb 22, 2011 at 6:24 PM, Paul Norman <penor...@mac.com> wrote: > Thanks for the background - that explains why some things are the way they > are and some of the oddities. > > For connector ways, I'd estimate that 95% of them are for very small bodies > of water without names or for rivers, where it does make sense to talk about > the river flowing through. For the relatively rare case of a large body of > water I could then revert it to sub_sea=* > > A typical example of a connector waterway is > http://www.openstreetmap.org/browse/way/72831492 > > NHN had no ways tagged as waterway=river, all the rivers were tagged as > waterway=stream or sub_sea=stream. An example of this is the Indian River, > which was tagged as sub_sea for approximately 20 km and then was a mix of > sub_sea=stream and waterway=stream for the remainder. > > I've found Bing's imagery in rural areas is often the same as that on the BC > openmaps server and very accurately aligned, so I was planning on using > Bing. Attribution will be preserved > > Anyways, back to the concerns about connector waterways. What would you > think about if I added in with step 5 reverting sections of waterways under > large lakes to sub_sea? > > I know that after doing all of these steps that some waterways may be > mistagged, but it should be significantly fewer than currently and after > simplification and joining named ways together it should be easier to go in > and edit. > > > >> -----Original Message----- >> From: Adam Dunn [mailto:dunna...@gmail.com] >> Sent: Tuesday, February 22, 2011 9:38 AM >> To: Paul Norman >> Cc: Talk-CA OpenStreetMap >> Subject: Re: [Talk-ca] Proposal: Cleanup of NHN ways in BC >> >> Right, the NHN import in the area mentioned was done by MBiker. MBiker >> was a pretty big mapper for the Vancouver area. He started off doing >> lots of manual edits by biking around and gps'ing, then he got involved >> in the NRN road import for east GVRD, then he did NHN for the entire >> watershed area (08X-something?). The problem with his NHN import was >> that he bit off more than he could chew. He was going around fixing and >> cleaning the NHN stuff he imported (like a good importer should do), but >> he suddenly stopped working on OSM in October. I think maybe the size of >> the import was too daunting for one man? >> >> The process used for importing NHN was different depending on how much >> was being imported at once. When an entire watershed was done (which is >> the case here), it was: >> 1. Download NHN watershed in .osm format from Yan's server. >> 2. Use one of the bulk upload scripts. >> 3. Download area from OSM with JOSM and fix any issues. >> >> For BC non-coastal watersheds, Canvec is equal to NHN. There was an >> issue with watersheds abutting against the coast, but I can't remember >> if this was resolved (and a quick search through my email history turns >> up nothing). >> >> Sam's purpose of the oneway=yes tag was twofold: to get waterflow >> direction arrows to render, and to show that the flow direction was >> verified (could have used a "direction_verified=yes" tag). This goes >> against the standard for OSM tagging of waterways, since the direction >> of the way itself implies waterflow direction. Mapnik doesn't render >> flow direction, but that's a matter of the renderer, not the data, just >> like Richard said. >> >> I don't think Sam's (or MBiker's) imports need to be wiped, since that >> would mean a couple months from now someone will just do the same thing >> from Canvec. Or if you are anti-import, you can delete the data, put on >> some bug spray and hiking boots and go map the streams yourself. >> >> Now to get back to the original question. >> >> I disagree that connectors should be upgraded to stream. On the talk-us >> list, they gave the example of a river still running through a man-made >> reservoir, so upgrading to stream would be okay, but in most cases, I >> don't think it would be appropriate. I think it would be incorrect to >> think that Chilliwack River flows underneath Chilliwack Lake or Sweltzer >> River flows through Cultus Lake. In most cases they shouldn't be >> rendered, since it only makes sense to have the lake rendered. It's not >> just a rendering issue though, I think connectors are logically >> different from normal waterways. The purpose of the connector ways (as >> far as I can think of) is for topological reasons. >> It's useful to see how different streams and rivers flow through lakes, >> and how they are connected to each other. We could ask, for example, >> "can a fish swim from Cultus Lake to Chilliwack Lake", or "if ammonium >> chloride spills into Slesse Creek, where will it end up?". >> This is why the connector ways are present. You could potentially make a >> script that analyzes inflowing and outflowing waterways connected to a >> lake, and makes the connectors automatically, but having the connectors >> there already makes it easier and verified. >> >> The difference between stream and river is size. Are there cases where >> waterways large enough to be rivers are tagged as stream in NHN? >> >> Be careful when selecting the better data based on imagery. The non-NHN >> waterways are probably traced from Yahoo, so using Yahoo to see which >> waterway is more accurate has obvious bias towards the non-NHN way. Try >> to use a third source (Bing), or look to see if there are obvious >> reasons to choose one over the other (eg. if Yahoo shows a stream >> redirected around new housing, then Yahoo is probably more accurate than >> NHN). >> >> Be careful removing source tag. We still need to acknowledge >> Geobase/NRCan as a source of at least part of the data. Keeping an >> attribution=Geobase Canada or attribution=Natural Resources Canada >> should be enough. >> >> Adam >> >> On Tue, Feb 22, 2011 at 7:43 AM, Paul Norman <penor...@mac.com> wrote: >> > As an aside, the imports in the lower mainland were not done by Sam, >> > but by mbiker. I'm not sure on the exact import process used for the >> > NRN data. If I were to do the imports over again myself I think I'd >> > use CanVec 7.0 which seems to have the same data but I haven't >> evaluated it in any detail. >> > >> > -----Original Message----- >> > From: Sam Vekemans [mailto:acrosscanadatra...@gmail.com] >> > Sent: Tuesday, February 22, 2011 6:52 AM >> > To: Kevin Michael Smith; Talk-CA OpenStreetMap >> > Subject: Re: [Talk-ca] Proposal: Cleanup of NHN ways in BC >> > >> > Cool, if i knew how to edit a stylesheet i would :) So t hat's fine. >> > >> > >> > So perhaps then it can be all changed with a bot? >> > >> > >> > ... or is it better to simply wipe my edits? >> > >> > >> > >> > The rivers (without oneway=yes tag) is available in another api, so >> > it's no big deal. >> > >> > >> > cheers, >> > Sam >> > >> > >> > On 2/22/11, Kevin Michael Smith <smit...@draconic.ca> wrote: >> >> On Tue, 2011-02-22 at 06:34 -0800, Sam Vekemans wrote: >> >>> Great! Were getting somewhere.. >> >>> >> >>> >> >>> Now lets discuss the most appropriate tag that can be used to >> >>> indicate the rendering of a flow line arrow. >> >> >> >> It's not about tagging the rivers to say 'there should be an arrow >> >> here', it's about putting 'Rivers have arrows' in the style sheet for >> >> the renderer. 'Having arrows' isn't a property of the river, it's a >> >> property of how we may or may not want to display it. >> >> >> >> -- >> >> Kevin Michael Smith <smit...@draconic.ca> >> >> >> > >> > >> > -- >> > Twitter: @Acrosscanada >> > Blogs: http://acrosscanadatrails.posterous.com/ >> > http://Acrosscanadatrails.blogspot.com >> > Facebook: http://www.facebook.com/sam.vekemans >> > Skype: samvekemans >> > IRC: irc://irc.oftc.net #osm-ca Canadian OSM channel (an open chat >> > room) @Acrosscanadatrails >> > >> > _______________________________________________ >> > Talk-ca mailing list >> > Talk-ca@openstreetmap.org >> > http://lists.openstreetmap.org/listinfo/talk-ca >> > >> > >> > _______________________________________________ >> > Talk-ca mailing list >> > Talk-ca@openstreetmap.org >> > http://lists.openstreetmap.org/listinfo/talk-ca >> > > > _______________________________________________ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
