[Talk-us] Relations and boundaries
Steve Friedl
steve at unixwiz.net
Thu Mar 3 19:02:44 UTC 2016
Hi all,
Ive been updating all the cities in Orange County California to have fully
segmented relationalized boundaries, such that cities sharing a common
border share a single way in each of their relations; this eliminates
overlapping ways. Its been very tedious but it's really getting cleaned
up.
So a few questions:
First: The individual relations city, county, national forest, etc. all
have full information tags about the entity, but how should the way members
themselves be tagged?
Ive seen some OSM notes that say the ways can be tagged too, but Im not
sure how. Theres no common name, and there may not even be the same admin
level (a city boundary on the border of a county would have two admin levels
for the given way.
My experience is that if the relation is fully tagged, and one of the ways
is tagged with the same info, we see duplicate city names along the border,
as the renderer takes the name from both the relation and the way.
I am not sure I see any value *other than* tagging it as a boundary, with no
other information. But Id really like to do this right.
Second: Im not sure how to handle quasi-enclaves. Orange county is made of
many cities, and a few cities contain some small *county* regions - think of
them as donut holes. I don't know how to handle this.
The Orange County relation is tagged with
boundary = administrative
border_type = county
admin_level = 6
The city of Westminster relation (fully inside Orange County) is tagged with
boundary = administrative
border_type = city
admin_level = 8
Within Westminster is a "donut hole" , and the Westminster relation has it
as a role=inner.
Question: should that same donut hole be tagged role=outer in the Orange
County relation?
It just doesn't feel right to have a role=outer fully within another
role=outer, but that's the only way I can think of to handle this.
Or do we just assume that because this donut hole has been excluded from the
City of Westminster, it's automatically part of the next outer item (in this
case, Orange County). The renderer doesn't identify any parts of the
donut-hole boundary.
The hole in question:
http://www.openstreetmap.org/#map=17/33.73488/-117.98422&layers=N it's just
to the west of Star View Elementary School There are many of these in
Orange County.
Steve
---
Stephen J Friedl | Security Consultant | UNIX Wizard | 714 345-4571
steve at unixwiz.net | Southern California | Windows Guy | unixwiz.net
More information about the Talk-us
mailing list