City Borders

I’m not sure what is the best way to tag city borders in Gush Dan, where one street is in one city and the next street is in another.

Also encountered:

  • as you move a long a street, you enter and exit a different city.
  • each side of a single belongs to a different city.

The obvious solutions would be either “is_in”, or a city area.

The tag is_in, while generally fits well to city borders, is a total mess,
and city areas are tough to get right on the edges and won’t hold when a border street is moved a little.

This is an important issue for routing applications.

So if you have any ideas, or can just tell what you have already done - please do.

I’m working on mapping Tel Aviv, and believe we will soon have enough boundary streets to be able to draw its place polygon.

I suggest split the way in the place boundary.
e.g. this is how streets are mapped in Europe

Using “is_in” is impractical for cities with many streets.
No one will go over all streets and add an “is_in” tag.

Since currently there are no rules, or exact guidelines to using “is_in”, I don’t believe it is a good solution.

See here:

e.g. San Francisco could be tagged in any of these ways:
is_in=California, CA, USA
is_in=USA, CA, California
is_in=California, CA, USA, North America, Earth, Milky Way

But using a polygon with a “place” tag is deterministic.
It is pretty easy to calculate whether a node or a way is inside a polygon.

It is also very easy to “fix” things, by altering the “place” polygon.

See here:

I believe option b1) is the best for us.
We don’t have administrative boundaries (e.g. option b2) that requires admin_level=8)

Administrative boundaries are used for e.g. phone numbers, or deciding where to vote, etc.

If there is no “place” polygon, then routing applications should fallback to “nearest city node”

OK, you convinced me. Polygons it should be.

These days I’m mainly on Ramat-Gan, Bney-Brak, Givataim.
Maybe we should push towards having the missing streets for those polygons, perhaps create a wiki page with a “most wanted” list, or maybe something here in the forum?

This is practically useless for this area.

I thought of something simular, too.

We could open a new thread where everybody can write down the status of his city (Everybody would like to know how far are the big cities!)
If you need some help in a specific area, just write in there and lets see if we can help somehow.

Or we could open a thread for the main cities like TelAviv, Jerusalem, Haifa, Netanya and so on. Everybody that needs help in some way mapping, editing or tagging could write in there and maybe he can find somebody for help…

what do you think ?

Givataim is practically ready. I think we’re missing only 2-3 streets, and some footways.

So I decided to try and create a polygon for it:

This is only an initial draft, from memory. I wasn’t sure in some places. I’ll fix it later.

I drew the polygon between the two lines of a two way separated streets.
It is quite a mess in some places: the streets position is probably no very accurate, and will have to be moved quite a lot, together with this new polygon.

Does any of you think that it will be possible to get an accurate information from the state / city in a license that will permit using it for osm? It would be very nice…

That’s cool.

The place polygon shouldn’t have the name* tags.
It should only have a place_name tag.
See Key:place under Tags used in conjunction | place_name=* :
The name of the place. place_name is used for closed ways drawn around the perimeter of a place, while the straightforward “name” tag is used on a central node.

If the polygon have a name tag, it would show twice (at least it’s like that in the Garmin created maps)
The node is where to place the name on the map.

You might also want to add landuse=residential to the polygon, which will show it on the rendered map.

It wouldn’t hurt to ask.
Need to ask in the Handasa Department of the city.
Most (all?) cities have a comprehensive GIS systems.
Maybe if we could persuade one city to donate theirs, other cities will follow?

I tried asking for permission to use the data of Netanya in a CC compatible license and once I got to the point of describing what the license means I never got a response from them. But I didn’t pursue it too much.

If we could get the data from the GIS systems we could have complete data easily. They do have all data of all streets and even building shapes. Netanya even have the information online.