• FCDOutput

The FCD (floating car data) export contains location and speed along with other information for every vehicle in the network at every time step. The output behaves somewhat like a super-accurate high-frequency GPS device for each vehicle. The outputs can be processed further using the TraceExporter tool for adapting frequency, equipment rates, accuracy and data format.

Instantiating within the Simulation#

The simulation generates this output when setting the option --fcd-output <FILE>. <FILE> is the name of the file the output will be written to. Any other file with this name will be overwritten, the destination folder must exist.

By default, fcd-output is enabled for all vehicles and persons in the simulation with output in each simulation step. Using device assignment options or parameters (i.e. --device.fcd.probability 0.25) the set of vehicles which generate fcd output can be reduced. The output period can be set by using option --device.fcd.period <TIME>. To delay output (i.e. until some warm-up time has passed), the option --device.fcd.begin <TIME> may be used.

Generated Output#

The generated XML file looks like this:

<fcd-export>

  <timestep time="<TIME_STEP>">
      <vehicle id="<VEHICLE_ID>" x="<VEHICLE_POS_X>" y="<VEHICLE_POS_Y>" angle="<VEHICLE_ANGLE>" type="<VEHICLE_TYPE>"
      speed="<VEHICLE_SPEED>"/>

      ... more vehicles ...

  </timestep>

  ... next timestep ...

</fcd-export>

The values without a tick in the "On" column need to be enabled explicitly and the ones without a tick at "Meso" are not available for the mesoscopic simulation.

When the option --fcd-output.geo is set, the written (x,y)-coordinates will be the lon/lat geo-coordinates.

Precision#

By default fcd-output returns location values in meter with a precision of 1cm. (changeable by setting option --precision). If you set option --fcd-output.geo the values are lon,lat as decimal values with a precision of 6 decimal places (changeable by setting option --precision.geo)

Person and Container Output#

Any persons or container in the simulation will cause output of he following form:

<fcd-export>

  <timestep time="<TIME_STEP>">
      <vehicle .../>
      ...
      <person id="..." x="..." y="..." angle="..." type="..." speed="..." edge="..." slope="..."/>
      ...
      <container id="..." x="..." y="..." angle="..." type="..." speed="..." edge="..." slope="..."/>
      ...
  </timestep>

  ... next timestep ...

</fcd-export>

If persons or containers are transported within a vehicle, their respective <person> and <container> elements will be written as child elements of that vehicle.

Filtering / Restricting Output#

Restricting the set of vehicles that generate output#

Output can be restricted to specific vehicle types or vehicle ids by controlling the set of vehicles that are equipped with the fcd-device. The following example restricts output to a single vehicle called ego:

--device.fcd.explicit ego

The following example restricts fcd-output to a single flow out of the whole simulation

--device.fcd.probability 0 ...

<flow ...>
   <param key="has.fcd.device" value="true"/>
</flow>

Restricting the set of persons and containers that generate output#

Output can be restricted to specific person or container types or person/container ids by controlling the set of persons that are equipped with the fcd-(person)-device. The following example restricts output to a single person called ego:

--person-device.fcd.explicit ego

The following example restricts fcd-output to a single personFlow out of the whole simulation

--person-device.fcd.probability 0 ...

<personFlow ...>
   <param key="has.fcd.device" value="true"/>
</personFlow>

Restricting the locations#

Output can be restricted to a specific set of edges by loading a list of edges from a file with option --fcd-output.filter-edges.input-file <FILE>. The file format for this is the same as the one when saving selections in netedit:

edge:id1
edge:id2
...

Restricting the locations by shape#

Output can be restricted to vehicles within a specified area by setting a list of <poly> ids with option --fcd-output.filter-shapes. The polygon shapes must have been loaded from an additional file.

Restricting output by sensor range#

When not all vehicles are equipped with an fcd-device, other vehicles and persons in a radius around the equipped vehicles can be included in the output by setting option --device.fcd.radius to the desired range in m.

Further Options#

• --fcd-output.geo will toggle output coordinates to WGS84 (for geo-referenced networks)
• --fcd-output.signals will add signal state information to the output
• --fcd-output.distance will add kilometrage information to the output
• --fcd-output.acceleration will add acceleration data to the output (also lateral acceleration when using the sublane model)
• --fcd-output.max-leader-distance FLOAT will add attributes leaderGap, leaderSpeed, leaderID whenever a vehicle has a leader within the given distance. Otherwise, leaderID will be "" and leaderGap, leaderSpeed will be -1.
• --fcd-output.params KEY1,KEY2,... adds generic parameters to the output (supports device and car-following model parameters as well as arbitrary user-define values)
• --fcd-output.attributes ATTR1,ATTR2,... restrict / extend written attributes to the given list to customize output (can be any combination of the attributes above). The value all enables all attributes.

NOTES#

In combination with the given geometry of the vehicles (shapes) you can build some nice animations, e.g NASA WorldWind or Google Earth.

Visualization example#

Accelerations versus distances#

Generated with plot_trajectories.py.

All trajectories over time#

Generated with plotXMLAttributes.py.

Generated with plot_trajectories.py.

Selected trajectories over time#

Generated with plotXMLAttributes.py.

Generated with plot_trajectories.py.

FCD based speeds over time#

Generated with plot_trajectories.py.