Setting parameters for PuT skim matrices

Note: Here, only the PuT-specific settings for skim matrices are described. You must also set global parameters for skim matrices (Setting metadata for skim matrices).

For skim data output regarding public transport you may select a unit for length data, a unit for time data and a unit for impedance data.

With the headway-based assignment or the timetable-based assignment you can return any direct or indirect time profile attribute as skim Path leg attribute. Specify the time profile attributes you would like to aggregate and the aggregate method. This way, a path attribute is determined from the attribute values of all path legs used by a time profile. If a path does not use any PuT lines, the result of this path is = zero, so that the path does not enter the weighting of all path values for a relation-based skim value.

Note: The skim Path leg attribute is not issued in PuT path lists.

The skim Discomfort due to capacity overload measures the time the passenger spends standing in the vehicle. The skim is calculated based on a formula that you can change (Fundamentals: Derived skims). The skim is only calculated with a timetable-based assignment and is always indicated in the unit seconds. The following prerequisites need to be fulfilled:

  • The paths are saved as connections.
  • The volumes of the demand segments for which discomfort is to be calculated are not saved to another demand segment.
  • To all OD pairs, demand > 0 applies.

Note: You can only calculate PuT skim matrices with a time reference to the arrival or departure time following the execution of a timetable-based assignment. If you calculate PuT skim matrices after headway-based or transport system-based assignments, neutral time references are allocated to the matrices.

1.  From the Calculate menu, choose General procedure settings.

The General procedure settings window opens.

2.  In the navigator, select PuT settings > Skims.

Note: In the skim table, you can make additional settings (Setting metadata for skim matrices).

3.  In the Units for skim matrices section, select the desired options.

Element

Description

Lengths

Unit for storing all skims of the Length data type, it is also used for skims of the Speed data type.

Select either Kilometers/Miles (long length) or Meters/Feet (short length).

Note

Whether metric or imperial units are provided depends on the current settings made under Network > Network parameters > Basis tab (Undoing and redoing actions).

Time

Unit for storing all skims of the Time/Duration data type, it is also used for skims of the Speed data type.

Select either Minutes or Seconds.

Impedance

Select Minutes or Seconds as unit for the skim impedance

Note: Visum does not store the data type of the selected unit but just saves whether a short length (Meters or Feet) or a long length unit (Kilometers or Miles) has been set. When you load data, the unit set under Network > Network settings > Basis is used. The values are re-calculated, if applicable.

4.  Next to Path leg attribute, click the Parameters button.

The Skim 'Path leg attribute' window opens.

5.  Click the <Attribute> button.

Note: The button is labeled with the currently selected attribute.

The Attributes (Time profiles) window opens.

6.  Select the desired attribute (Selection of attributes).

7.  Confirm with OK.

8.  In the Aggregate function selection list, select the desired entry.

Element

Description

Average

Mean value of all attribute values

AvgActive

Mean value of all attribute values of active time profiles

Max

Maximum of all attribute values

MaxActive

Maximum of all attribute values of active time profiles

Min

Minimum of all attribute values

MinActive

Minimum of all attribute values of active time profiles

Sum

Sum of all attribute values

SumActive

Sum of all attribute values of active time profiles

9.  Confirm with OK.

10.  Next to Discomfort, click the Parameters button.

The Skim Discomfort window opens.

11.  Enter the required parameter values.

Note: The values need to be ≥ 0.

12.  Confirm with OK.

The parameters for the PuT skim calculation have been set.