HERE Traffic TPEG API
Traffic TPEG API Developer's Guide

# Multi-Radius proximity example for getmessages

All Multi-Radius getmessages requests must be preceded by an initsession request (which contains the Getmessage URL) and must be encrypted as described in Get started. The following request body shows a request for traffic information around the point defined by latitude 52.5158426 and longitude 13.412532. The radius is defined in the getmessage Multi-Radius request.

<?xml version="1.0" encoding="UTF-8" ?>
<get-messages>
<locations>
<loc lat="52.5158426" lon="13.412532"/>
</locations>
<filters>
</filters>
</get-messages>

Usually, you need to filter traffic data based on types of the road, because there is no need to display detailed traffic information for long distances from the current position. To decrease the traffic data amount exchanged between the server and client, the TDA service has the ability to filter TPEG messages depending on their Functional Classes (FC).

FC is a road type indicator, reflecting traffic speed and volume, as well as the importance and connectivity of the road. The following values are supported:

• 1: a road with high volume, maximum speed traffic.
• 2: a road with high volume, high speed traffic.
• 3: a road with high volume traffic.
• 4: a road with high volume traffic at moderate speeds between neighborhoods.
• 5: a road whose volume and traffic flow are below the level of any other functional class.
The following is an example of how an API would be able to request traffic with given filtering:
• radius 10 km → FC from 1 to 5
• radius 20 km → FC from 1 to 3
• radius 60 km → FC 1

Each larger radius excludes all previous smaller iteration, therefore only the smallest radius becomes a circle, while all others become rings.