Vector Flow Tiles - how to interpret obtained messages?

REST APIs
#1

Hello,
I am trying to see if I can extract useful information from the Traffic Flow API.
I found that ‘Flow Segment Data’ returns very good flow data, however it costs a lot of transactions since it reports only the closest single flow data.
Now I am trying with ‘Vector Flow Tiles’, but I can not obtain the flow data such as:

currentSpeed, freeFlowSpeed, currentTravelTime, freeFlowTravelTime, confidence, roadClosure, coordinates.

Instead I get:

  features {
    tags: 0
    tags: 21
    tags: 1
    tags: 7
    tags: 2
    tags: 13
    tags: 3
tags: 3
type: LINESTRING
geometry: 9
geometry: 703
geometry: 9012
geometry: 10
geometry: 115
geometry: 273
  }

What I interpret is that the ‘tags’ are always paired and correspond to

tags: 0  ------>  keys: "road_type"
tags: 21
tags: 1  ------>  keys: "traffic_level"
tags: 7
tags: 2  ------>  keys: "traffic_road_coverage"
tags: 13
tags: 3  ------>  keys: "travel_mode"
tags: 3

however I can not understand what their value numbers “road_type” : 21, “traffic_level” : 7, “traffic_road_coverage” :13, “travel_mode” : 3 represent.

I also have received bunch of value messages :

  values {
    string_value: "Motorway"
  }
  values {
    double_value: 100.0
  }
  values {
    string_value: "full"
  }
  values {
    string_value: "bridge"
  }
  values {
    string_value: "Secondary road"
  }
  values {
    double_value: 5.0
  }
  values {
    double_value: 10.0
  }
  values {
    double_value: 15.0
  }
  values {
    double_value: 20.0
  }
  values {
    double_value: 25.0
  }
  values {
    double_value: 30.0
  }
  values {
    double_value: 35.0
  }
  values {
    double_value: 40.0
  }
  values {
    string_value: "one_side"
  }
  values {
    double_value: 50.0
  }
  values {
    double_value: 0.0
  }
  values {
    bool_value: true
  }
  values {
    bool_value: true
  }
  values {
    string_value: "Connecting road"
  }
  values {
    string_value: "Major local road"
  }
  values {
    string_value: "Local road"
  }
  values {
    string_value: "Minor local road"
  }

Which I don’t get what refers to where.

Once again my current aim is to get ‘currentSpeed, freeFlowSpeed, currentTravelTime, freeFlowTravelTime, confidence, roadClosure, coordinates’ information of flow items in an area.
Do you know how to achieve this?

#2

Similar discussion: Parsing Incident flow API response

#3

Thank you for your reply, it helped me a lot.

However I am still wondering if it is possible to get ‘absolute free-flow speed’ and ‘confidence’.

#4

This service doesn’t return that values.
You could try to ask for absolute and relative values and do some calculations but this is not documented and I’m not sure if would give reasonable values.