I'm just getting started working with TMC (Traffic Message Channel) data and I'd like to know how to use the location codes to get coordinate data for points. Is there a mapping somewhere I could use? I'm considering using traffic data from TTWN for the US.
You need the Location Code List for the area you are interested in. However, there is a catch: there are free and commercial TMC services. The latter either keep their location tables secret or encrypt their data. In order to get the location tables or the decryption key, you would presumably have to sign a license agreement or NDA and pay a royalty, likely per user or device. To my knowledge, all US services fall into this category. Europe has a mix of both, and some location code lists are freely available.
If you are just curious and would like to see how it works, here are some pointers:
- RDS Surveyor—an RDS/RDBS parser application and library which can also handle TMC and decode TMC locations if you supply a location table. RDS input can come from a file or a hardware receiver.
- OSM TMC#Available datasets—list of public TMC location tables
- RDS Spy Logs is a repository of RDS data captures which you could use for analysis. RDS Surveyor can read them, though not all have TMC data.