"counts". Status: works for vsp and ivt

Maintenance and Questions:

A. Horni, IVT (horni_at_IVT.baug.ethz.ch)

Javadoc:

www.matsim.org/javadoc/org/matsim/counts/package-summary.html

Config Parameters

www.matsim.org/javadoc/org/matsim/counts/package-summary.html#counts_parameters

In Brief:

MATSim can compare the simulated traffic volumes to traffic counts from the real world. Counts is the module that allows to

• read some external file with traffic flow counts
• compare them automatically to the counts generated inside the matsim simulation
• submit the result to a kmz file which can be displayed inside google earth

There is a feature to re-scale the counts before comparison (for example if you are running the simulations with a 10% sample).

Comparison Data

Prepare a file containing the real-world traffic counts. The file, e.g. named counts.xml, must follow the xml-format defined in counts_v1.xsd. An example of such a file can be found in MATSim at examples/equil/counts100.xml.

The file contains the following information:

• For each link in the network for which traffic count information is available, a count-element must exist. The count-element specifies the link it refers to in its attribute loc_id. In addition, an optional cs_id can be stored that may, for example, refer to the original id of the counting station (for tracking back the origin of the data).
• In each count-element, 1 to 24 volume-elements can appear. Each volume-element contains the measured traffic count (attribute "val") for an hour of the day (attribute "h", numbered from 1 to 24; 1 = 00:00-00:59, 2 = 01:00-01:59, etc). It is not necessary that traffic counts are available for all 24 hours of a day.

Enabling Comparison in Configuration File

Add the following lines to your configuration file:

<module name="counts">
  <param name="inputCountsFile" value="/path/to/counts.xml" />
  <param name="outputformat" value="txt,html,kml" />
</module>

The comparison is automatically generated every 10th iteration. Generated output is located in the output-directory of the iteration (usually something like output/ITERS/it.10/).

Configuring the Counts Comparison

The counts-module offers the following config-parameters:

• <param name="outputformat" value="txt,html,kml" />
  The output format specifies in which format the comparison results are written to disk. It can be any combination of txt, html and kml. Multiple formats can be specified separated by commas. txt writes simple text-tables containing the values to a file. It is most useful to create custom graphs, e.g. in Excel. html creates a directory containing several html files, allowing to browse the results interactively. kml creates a file to be displayed in Google Earth. This last option only works if the correct coordinate system is set.
• <param name="countsScaleFactor" value="1.0" />
  If you only simulate a sample of your population, the simulated traffic volumes are likely lower than the real-world traffic counts. In order to allow useful comparison, one can specify a factor by which the simulated traffic volumes are multiplied. For example, if you simulate a 25% sample of your full population, specify a countsScaleFactor  of 4.
• <param name="distanceFilterCenterNode" value="2386" />
<param name="distanceFiler" value="30000.0" />
  If the traffic counts cover a larger area than the area being simulated, the traffic counts outside your area will result in a bad comparison. Instead of removing the traffic counts from the counts.xml, you can specify a filter to only include some traffic counts from the file in the comparison. To activate the filter, specify the id of a node that acts as the center of a circle. The circle has the radius specified in "distanceFilter", the unit being the same unit as the length of links (i.e. usually meters).