In our journey of improving the OpenStreetMap we are constantly searching for open source data. This search is very important and is done before we start improving the map in a new area.
Currently, part of our team is focused on improving the Detroit area. So, before we started mapping we searched for useful geospatial data and we came across open data about traffic signals and stop signs for Wayne County, Detroit. The data can be found here and here.
We filtered out the traffic signals and stop signs that were already in OSM but there is still a significant amount of data that can be added in OSM. (912 – traffic signals and 8755 – stop signs). Due to this, we thought about creating a MapRoulette challenge.
MapRoulette is a micro-tasking tool used to fix bugs in OpenStreetMap and to improve it. A user can create tasks by uploading files which contain the location, ways, points with the error that has to be fixed or files with features that are missing from the map and can be added by other users.
When creating a new task, the user gives specific instructions on what steps have to be followed to edit through this tool. Once a user has logged in, he can see on the map the created challenge and the pins which consists of tasks he can solve.
So, given the available data that we found, we created two challenges – one for traffic signals and the other for stop signs. Some general rules for mapping traffic signals and stop signs can be found on the OSM wiki – here and here.
Tags that we use for mapping
- Stop signs – highway=stop
- Traffic signals – highway=traffic_signal
- If the traffic signal/stop sign is referring to all the highways entering the intersection, we add the traffic signal/stop sign in the intersection point.
- If the traffic signal/stop sign is not referring to all the highways entering the intersection we add the traffic signal/stop sign before the intersection, where the sign/signal is positioned.
- We need to add an additional tag if the road is bidirectional:
- for traffic signals we use the traffic_signals:direction key with the forward or backward values to indicate the affected direction.
- for stop signs add direction=forward or direction=backward to indicate the affected direction.
The data has been published under Public Domain license.
Everyone who is keen on mapping is welcomed to help us.
Let’s improve OSM together!