OpenStreetMap

Mapping private subdivision roads and other gated roads

Posted by TagaSanPedroAko on 8 January 2016 in English (English)

The former way of mapping private subdivision roads is to mark all roads within the subdivision’s (or other gated area, such as on industrial parks or some cases, residential areas of some barangays) grounds with “Private” (tag:access=private) access. However, it is incorrect, because the Private tag will prevent routing. So, changes in the [Philippines Mapping Conventions] (http://wiki.openstreetmap.org/wiki/Philippines/Mapping_conventions) are made. The changes is to mark the subdivision (or other gated area) [road] entrances with the gate=* tag, plus the access tag, rather than to tag the roads’ access with the access attribute. Access attributes will be on the roads will be placed on the gates, so, that attribute does not impede routing. Access tags for gates may be destination (local traffic only and no through traffic), permissive (allows entry by payment of a fee, which should not be confused with tolls, which are rather tagged as toll=yes.), or private (in this case, the gates restricts access to vehicle, usually with stickers issued). But mostly, it is best to mark subdivision (or other gated area) roads’ gates as access=destination, so it will allow routing to a place within its grounds, because there are visitors outside of the grounds will go to a place within the area (such as a house, business, a school, like in some cases, or other place.).

Comment from Sanderd17 on 8 January 2016 at 11:47

Where did you get the fee thing for access=permissive? AFAICS, access=permissive means it’s owned by a private person or company, but the owner allows free traffic over the way (so no fee situation is no different from public roads, though they could theoretically as a toll, just like public roads).

In general, routers should know, if your start or end point is near a road with access=destination, access=private or any of those partial access tags, it’s because you’re already there, or you need to get there (and will take care of getting legal access). So the routers should be able to route you over those roads without problem, but they can’t route you through.

When you tag the barrier, how would routers know if you can pass the barrier? There’s no difference between a bollard to prevent through-traffic in a suburb road, or a bollard before a private road (f.e. an emergency road). Both could also be removable by authorised people (emergency operators, inhabitants, …), so tagged with some other access tag than access=no.

I know that routers have difficulties with this (they usually just have passable or not passable road classes, and nothing in-between), but this isn’t a reason to tag it differently. It’s a reason to improve the routers out there.

Moreover, you’re now making the access tags invisible (it’s easy to render access tags on roads, while it’s hard to render them on a barrier node), and the only reason it works now is because most routers still don’t understand how access-tagged barriers work and just ignore them.

One extra argument: it’s not because something is legally classified as having a certain access, that there’s also a barrier enforcing that access. We have many streets that are marked as access=destination by a sign, but have no barrier whatsoever.

I do believe in a local tag creation process (we don’t know how streets look like in the Philippines), but I think this way of tagging will seriously harm the OSM data consistency, and will make the job for routers a lot harder.

Comment from Vincent de Phily on 8 January 2016 at 11:57

+1 this calls for improving routing software, not routing/permission data.

Comment from TagaSanPedroAko on 8 January 2016 at 12:00

“Permissive” means through traffic allowed through the gate (barrier), either with or without a fee.

“Destination” is already clearly defined, and it means local traffic only (not to be used for through routing).

Comment from TagaSanPedroAko on 8 January 2016 at 12:11

Also, tagging things here in OpenStreetMap may be localized. But, clarifying things would be better. A barrier tagged with access=private will not allow traffic to pass through on some routers, but not all may understand it. It is correct to have the access included on the roads, so I do.

Additionally, the “Private” tag will apply to a road owned by a private individual and access is restricted to those with access to their property.

Comment from naoliv on 8 January 2016 at 12:59

This is “mapping for the router”.
Like people said before, the routing program should be able to deal with the private roads (and you should just not remove this info from them).

Comment from karussell on 24 February 2016 at 10:46

Author of a routing engine here: yes, please avoid mapping for the router. Customization of a routing engine which tags are allowed and which not should be easy. Also if there is a gate with a private tag then a “proper routing engine” would still avoid going through it.

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