ImproveOSM has been updated with many new roads. We processed recent GPS data from a number of data partners with some great results. A total of 30,000 new missing road tiles were added, over 17000 in Indonesia alone.
Aside from the missing roads, we added 67000 potential missing one-way roads that we detected with high confidence. Internal testing revealed only 6% false positives.
We are happy to continue providing OSM mappers with high quality data about missing things in OSM based on billions of GPS traces. Because ImproveOSM is based on actual drives from people using navigation or mapping software in their vehicles, and we apply a pretty high threshold for number of trips and quality of the GPS data, you can be pretty confident that every ImproveOSM feature will lead you to something you can add to OSM. Even if the aerial imagery is poor.
You should see the new data in your ImproveOSM plugin or on the ImproveOSM web site very shortly. Happy mapping and let us know what you mapped using ImproveOSM!
In a new data release today, we added about 500 tiles worth of missing roads in and around Guatemala!
We are excited to be adding more and more Missing Roads data to ImproveOSM using GPS data from our own users as well as from data partners, like we did in Brazil and in this case.
You will notice that the tiles look a little different from the ones you are used to if you have used ImproveOSM before: they don’t show the individual points. This is because this particular data was processed a little differently. If you use JOSM, you will also see an update to the ImproveOSM plugin to accommodate this change.
While you are looking at the new Missing Roads, perhaps you will also notice some other recent improvements to the ImproveOSM web site. We re-ran all tiles based on new map data from mid-April, and we improved our turn restriction detection so we won’t show a missing turn restriction when OSM already has a ‘only straight on’ restriction.
The best part of using everyday OSM technologies and relying on OSM to make sure that you get “there” on time is that you can directly influence the quality of the experience.
Regardless which OSM technology you’ll be using, to provide you the best experience possible, the routing software has to know as much information as possible about the roads between you and your destination: one-way streets, turn restrictions, speed limits, road closures and much more.
For example, the turn restrictions contribute significantly to the total travel time, and to the correctness of the route altogether, thus, by ignoring them in the traffic network model, essential characteristics of the network might be missed, leading to substandard and unreasonable paths.
Dealing with turn restrictions in OSM
To help us navigate the complexities of properly translating real map scenarios to the ways and points schema of OSM we will rely on JOSM with the turn restrictions plugin installed.
Turn restrictions in OSM are handled by creating a relation
A relation is one of the core data elements that consists of one or more tags and also and ordered list of one or more nodes, ways and/or relations as members which is used to define logical or geographic relationships between other elements. (source)
There is a mandatory requirement when creating a turn restriction relation: it has to consist of minimum three members and must have assigned two tags. (see below example)
A ‘no_’ type relation can also be represented in map data as an ‘only_’ type relation. The prohibited turn restriction relation is preferred by some routing engines instead of an allowed turn restriction relation.
Members of a turn restriction relation are ways and nodes
One simple case can be a turn restriction relation that consists of three members – two ways and one node. The two ways would represent the beginning (‘from’ role) and end (‘to’ role) of the turn restriction. The node would represent the continuity of travel between two ways and has a ‘via’role.
Another case is where a turn restriction relation can consist of three or more ways. Two ways from this type of relation would represent the beginning and end of the turn restriction and at least one way would represent the continuity of travel between the aforementioned ways (‘via’ role).
Workflow for adding turn restrictions
The traditional way
Using the embedded relation editor available in JOSM. A slight disadvantage of this method is that you spend a bit more time to manually construct the relation. Click on the image below for how-to video.
The user-friendly way
Using the turn restrictions plugin, that automatically recognizes the type of relation and roles for each member. Click on the image below for how-to video.
Using the aforementioned tools, we have reviewed 2,000 miles of field trip footage and added nearly 2,500 turn restrictions in the LA/Orange county area, where 85% of the turn restrictions that were added to the map are no_u_turns, followed by 11% of no_left_turns, the rest being covered by the other categories.
Hopefully we’ve managed to illustrate how easy is to map turn restrictions in OSM. Now, it’s your turn!