[Talk-us] I think I got this right...

Martijn van Exel m at rtijn.org
Mon Jan 23 18:14:34 UTC 2017


Well, in this case, the only way to know for a routing application what the cardinal direction is, is to look at the member roles. Either that our you slice the relation up even more to have separate relations for east / west / north / south, which to my mind would make for a too-convoluted relationship hierarchy. What is your thought on indicating cardinal direction in this case if not as member role?

Martijn van Exel

> On Jan 22, 2017, at 5:24 AM, Paul Johnson <baloo at ursamundi.org> wrote:
> 
> On Sat, Jan 21, 2017 at 6:11 PM, <richiekennedy56 at gmail.com <mailto:richiekennedy56 at gmail.com>> wrote:
> Regarding the use of child relations for routes, and what to do about directional roles on beltways, I made some mapping changes to a beltway that happens to be local to me.
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> I took the relation for I-435[1] and “cloned” it into 2 new relations in JOSM[2][3]. I then deleted all ways from the in the relation and added the new relations, turning the old relation into the parent. As 435 is a beltway, I added “(clockwise)” and “(counterclockwise)” to the new relations. Milepost 0 on I-435 is the junction with I-35 at the southwest corner and the mileposts increase going clockwise (and do not reset at the state line) so I used the I-435 bridge over I-35 as my starting point. Starting there, I organized the ways in the clockwise direction in the JOSM relation editor. Once I had created a “loop,” I removed all the other ways from the clockwise relation, then selected the members of the clockwise relation to remove them from the counterclockwise relation. I then sorted out the ways for the counterclockwise direction in the same way.
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> I left the directional roles (i.e. “north,” “south,” “east,” and “west”) intact to represent how the segments on 435 are signed, and changed roles previously marked as “forward” back to directional roles. I also happened to find that I had inadvertently left a gap in the counterclockwise direction in the Johnson County Gateway project. I also noticed someone has previously attempted to note the direction in the “ref” tag. I changed those as well.
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> Aside from the fact that JOSM does not support the use of directional roles, I think the changes should make it cleaner for future mappers.
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> [1]: http://www.openstreetmap.org/relation/62155 <http://www.openstreetmap.org/relation/62155>
> [2]: http://www.openstreetmap.org/relation/6898835 <http://www.openstreetmap.org/relation/6898835>
> [3]: http://www.openstreetmap.org/relation/6898836 <http://www.openstreetmap.org/relation/6898836>
> 
> It would be easier to verify by using forward in the child relations exclusively.  Then it will validate as a loop, or it won't, and the gap becomes immediately apparent.  As tagged, most tools (JOSM included) won't "get" it.
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