Martijn I'm good with having a separate discussion of milepoints/*pointes kilometriques, *sure. I'll probably wait a week or two until a consensus emerges on posted directionality, as you suggest.
Peter On Thu, Nov 28, 2013 at 10:37 AM, Martijn van Exel <m...@rtijn.org> wrote: > Peter, > I think we should separate the discussion related to linear > referencing / mileposts from the cardinal direction discussion - these > are two different things really, to my mind. The notion of cardinal > direction is a relatively straightforward one, and that is already > cause for (cultural) confusion. Introducing the GIS concept of linear > referencing into this discussion I think adds to the confusion. We > should perhaps discuss that separately - I for one don't see the > immediate relation between the two, but I am happy to be proven wrong. > > On Wed, Nov 27, 2013 at 3:08 AM, Peter Davies <peter.dav...@crc-corp.com> > wrote: > > Martijn > > > > I, too, await your clarification for KristenK, as I'm a little confused > too. > > > > We need to keep in mind that positive and negative GIS Linear Reference > > directions (which are handy as global solutions applying everywhere in > the > > US at least) beginning at milepoint 0.0, usually on the southern or > western > > state boundary for rectangular states, are not the same as posted DOT > miles > > that sit on green and white pressed steel signs on the shoulder of all > > Interstates and many state/US routes. DOT miles often jump and can > > occasionally change directions, as route designators are altered > (something > > that happens quite often) and bypasses are built. The cost of reporting > the > > whole route is usually prohibitive. > > > > So GIS LRS positive and (imperfect) posted DOT miles are handy things to > > keep in mind as long as we realize that there are always a few > exceptions to > > break our defaults. Similarly, posted cardinal directions are fairly > > rules-bound but certainly not 100%. This is why I think a good OSM > solution > > needs to be explicit rather than implicitly inferred from highway > geometry. > > > > Examples of state GIS definitive records are built by ESRI "Roads and > > highways" (used in Indiana) and by Agile Assets (used in Idaho). Check > out > > http://www.esri.com/software/arcgis/extensions/roads-and-highways > > > > Peter > > > > > > On Tue, Nov 26, 2013 at 5:24 PM, Kristen Kam <krist...@telenav.com> > wrote: > >> > >> Martijn, > >> > >> I want to make sure I understand what you're trying to convey to the > >> group. Are you saying that If a way has a member role value of "east" > >> then east will mean forward and then west (it's opposite) would mean > >> backward? > >> > >> Example logic: > >> > >> ** If member role = east, node direction is eastbound would mean > >> forward and backward would mean 'west' > >> ** If member role = west, node direction is westbound would mean > >> forward and backward would mean 'east' > >> ** If member role = north, node direction is northbound would mean > >> forward and backward would mean 'south' > >> ** If member role = south, node direction is southbound would mean > >> forward and backward would mean 'north' > >> > >> If the logic I stated above successfully captured with your > >> suggestion, then I would like to expand on it. Why not just make the > >> cardinal direction value-forward/backward value relationship a bit > >> more simpler? I would like to cite Peter Davies' discussion on the > >> Highway Directions in the US wiki page. He stated that milepoints > >> increase as highways that trend northward or eastward--say positive > >> direction. So if one is traveling south or west on a highway, the > >> milepoints are decreasing--say negative direction. > >> > >> With this in mind, couldn't we just say that north/east = forward > >> (forward movement is positive!) and west/south=backward (backward > >> movement is negative!)? If we're digitizing our edges, the suggestion > >> would be to set the node direction of two-way, aka single-carriageway > >> roads, into a positive direction and the member roles values to north > >> or east. Basically what you did for > >> http://www.openstreetmap.org/browse/relation/2308411, but setting the > >> single-carriageway/two-way roads to 'east' instead of 'west'. > >> > >> Thoughts Martijn? Others?? > >> > >> Best, > >> > >> Kristen > >> --- > >> > >> OSM Profile → http://www.openstreetmap.org/user/KristenK > >> > >> > >> -----Original Message----- > >> From: Martijn van Exel [mailto:m...@rtijn.org] > >> Sent: Tuesday, November 26, 2013 2:47 PM > >> To: Ian Dees > >> Cc: Florian Lohoff; OpenStreetMap-Josm MailConf; OSM US Talk > >> Subject: Re: [Talk-us] [josm-dev] Relation editor support for > >> north/south and east/west similar to forward/backward > >> > >> Yes, sorry for not being clearer. As Ian indicates, this is the > >> *signposted cardinal direction* of a numbered road route, which does > >> not change with the actual compass direction of the road. The guiding > >> principle for the United States is that the odd numbered Interstates > >> are north/south, and the even numbered Interstates are east/west. This > >> is independent from the local compass direction. So for example, I-80 > >> is east-west, but runs almost north-south locally (for example here: > >> http://www.openstreetmap.org/browse/way/203317481) but the sign would > >> still say 'I-80 East' (or West as the case may be). > >> > >> So the relation between the east--west and north--south member roles > >> is equivalent to the relation between forward--backward. > >> > >> Because the cardinal direction is commonly included on the road signs > >> (see example > >> http://www.aaroads.com/west/new_mexico010/bl-010_eb_at_i-010.jpg) > >> this information is useful in the U.S. (and Canadian) context as a > >> drop in replacement for the traditional forward / backward role > >> members. > >> > >> Hope this clarifies somewhat! > >> Martijn > >> > >> On Tue, Nov 26, 2013 at 2:57 PM, Ian Dees <ian.d...@gmail.com> wrote: > >> > On Tue, Nov 26, 2013 at 3:51 PM, Florian Lohoff <f...@zz.de> wrote: > >> >> > >> >> On Tue, Nov 26, 2013 at 12:30:25PM -0700, Martijn van Exel wrote: > >> >> > Hi all, > >> >> > > >> >> > I'm new to this list so please bear with me. > >> >> > The relation editor currently only parses 'forward' and 'backward' > >> >> > roles when considering the visual representation in the rightmost > >> >> > column. In the United States, north/south and east/west are very > >> >> > common as member roles for road routes, because that is how they > >> >> > are officially signposted. > >> >> > >> >> I would be very careful in using this. Is this really "south" e.g. > >> >> 180° ? Or is it more like 99° ? Or 269° ? > >> >> > >> >> Most streets are not strictly on the 90° raster and signposts are > >> >> only rough directions. > >> >> > >> >> Addings this to OSM might make it much more difficult for Data > >> >> Consumers to process and interpret data. > >> > > >> > > >> > No, these aren't compass directions. They're the directionality of the > >> > road. > >> > For example, this way is part of the I-94 interstate going west, but a > >> > compass in a car driving on it would tell the viewer they were > >> > pointing > >> > north: > >> > > >> > http://www.openstreetmap.org/browse/way/39372612 > >> > >> > >> > >> -- > >> Martijn van Exel > >> http://oegeo.wordpress.com/ > >> http://openstreetmap.us/ > >> > >> _______________________________________________ > >> Talk-us mailing list > >> Talk-us@openstreetmap.org > >> https://lists.openstreetmap.org/listinfo/talk-us > > > > > > > > -- > Martijn van Exel > http://oegeo.wordpress.com/ > http://openstreetmap.us/ >
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