Setting parameters for the calculation of PrT skim matrices

Analyzed OD pairs

Element	Description
Filter selection list	With this selection list, the analyzed OD pairs that comply with the current setting of option Calculate only OD pairs with demand > 0 can be reduced further. Note For OD pairs that are not evaluated according to the current option settings, the skim matrix contains the value set for Ignored OD pairs under Calculate menu > General procedure settings > PrT settings > Skims (Setting metadata for skim matrices). All If this option has been selected, all OD pairs are regarded. Only active OD pairs If this option has been checked, only active OD pairs are regarded. Only active origin zones If this option has been checked, only OD pairs with an active origin zone are regarded. Only pairs of active zones If this option has been checked, only OD pairs connecting active zones are regarded. Notes The setting of the analyzed OD pairs specified for the calculation of skim matrices can differ from the setting for the assignment. If a restricting zone interval has been set for assignment, this will reduce the number of analyzed OD pairs even more. When reading parameters from an elder Visum version file the original selection for this option will be interpreted as either All or Only pairs of active zones.
Calculate only OD pairs with demand > 0	If this option has been checked, only OD pairs with demand > 0 are regarded. Note For OD pairs with demand = 0, skim value 0 is used.

Element

Description

Filter selection list

With this selection list, the analyzed OD pairs that comply with the current setting of option Calculate only OD pairs with demand > 0 can be reduced further.

Note

For OD pairs that are not evaluated according to the current option settings, the skim matrix contains the value set for Ignored OD pairs under Calculate menu > General procedure settings > PrT settings > Skims (Setting metadata for skim matrices).

All

If this option has been selected, all OD pairs are regarded.

Only active OD pairs

If this option has been checked, only active OD pairs are regarded.

Only active origin zones

If this option has been checked, only OD pairs with an active origin zone are regarded.

Only pairs of active zones

If this option has been checked, only OD pairs connecting active zones are regarded.

Notes

The setting of the analyzed OD pairs specified for the calculation of skim matrices can differ from the setting for the assignment.

If a restricting zone interval has been set for assignment, this will reduce the number of analyzed OD pairs even more.

When reading parameters from an elder Visum version file the original selection for this option will be interpreted as either All or Only pairs of active zones.

Calculate only OD pairs with demand > 0

If this option has been checked, only OD pairs with demand > 0 are regarded.

Note

For OD pairs with demand = 0, skim value 0 is used.

Path choice, Sum up paths from

Element	Description
Path search criterion	Criterion for selection of one or several paths per OD pair from which the relation's skim value is gained. t0 Path with shortest travel time in unloaded network tCur Path with shortest travel time in loaded network Impedance Depends on the current selection for option Use paths from assignment. If this option has not been checked, the path with the lowest impedance for the private transport system according to the current impedance function is used If this option has been checked, the aggregate value resulting from all paths is used Distance Path with shortest length AddValue1, AddValue2, AddValue3 Path with minimum AddValue Note The option is not available for the Calculate dynamic PrT skim matrix procedure.
Use paths from assignment	f this option has been checked, the skim value is gained from all paths per OD pair according to the current option Weighting of paths setting. If this option has not been checked, the path with the lowest impedance for the private transport system according to the current impedance function is used Notes This option is only provided if Impedance has been selected as path search criterion. The option is not available for the Calculate dynamic PrT skim matrix procedure. If paths exist from the Simulation-based dynamic assignment procedure, they will be used. Otherwise the shortest paths with the impedance from the simulation-based assignment are sought.
Weighting of paths	Method for skim value determination from the skims of all paths resulting from assignment Minimum per skim Value of the path with the smallest value Maximum per skim Value of the path with the highest value Mean over paths Mean value calculated from all paths Mean over path volume Mean value calculated from all paths and weighted by the particular path volumes Notes This option is only provided if the option Use paths from assignment has been selected. The path with the lowest impedance is determined for OD pairs for which no paths were calculated during assignment.
Sum up paths from	The skim value results from the data of the network objects of selected network object types over the selected paths. Links Turns (main turns included) Origin connectors Dest. connectors

List of PrT skims

Element	Description
List of skims	Calculate If this option has been checked, the particular skim is calculated. Save to file If this option has been checked, the particular skim is saved as skim matrix file. For further output settings please refer to the Output file section (Output file of a PrT skim matrix). For each skim that is to be saved to file, Visum creates a file with a skim-specific file extension which has been derived from the English abbreviation. Notes Skim matrix files created with previous Visum versions have file extensions that differ by language. These may even have been replaced by user-defined file extensions. This option is grayed out as long as option Calculate is not selected. Tip Each of the columns mentioned above can be checked or unchecked completely as follows: In the column header, right click to call the context menu and click either Activate column or Deactivate column. Skim List of available skims (Fundamentals: PrT skims)
Additionally calculate skim data per analysis time interval	If the option has been selected, you can calculate skim matrices with a time reference per analysis time interval: Departure time-related calculation If the option has been selected, the departure time is used as reference point for the calculation. Arrival time-related calculation If the option has been selected, the arrival time is used as reference point for the calculation. The skims are calculated weighted by volume. Notes The option is only available with the procedure Calculate dynamic PrT skim matrix. In this calculation it is important to consider the travel times for the assignment time period in your network. If you are interested in the skims of the margin intervals, make sure that demand exists and that the assignment time period is chosen in such a way that the end of the travel time lies within the analysis time intervals considered. Example: If the longest travel time in your network is 40 minutes, the assignment time period should start at least 40 minutes before the interval that you want to evaluate. Moreover, demand must already exist at the beginning of the assignment time period.

Element

Description

List of skims

Calculate

If this option has been checked, the particular skim is calculated.

Save to file

If this option has been checked, the particular skim is saved as skim matrix file. For further output settings please refer to the Output file section (Output file of a PrT skim matrix). For each skim that is to be saved to file, Visum creates a file with a skim-specific file extension which has been derived from the English abbreviation.

Notes

Skim matrix files created with previous Visum versions have file extensions that differ by language. These may even have been replaced by user-defined file extensions.

This option is grayed out as long as option Calculate is not selected.

Tip

Each of the columns mentioned above can be checked or unchecked completely as follows: In the column header, right click to call the context menu and click either Activate column or Deactivate column.

Skim

List of available skims (Fundamentals: PrT skims)

Additionally calculate skim data per analysis time interval

If the option has been selected, you can calculate skim matrices with a time reference per analysis time interval:

Departure time-related calculation

If the option has been selected, the departure time is used as reference point for the calculation.

Arrival time-related calculation

If the option has been selected, the arrival time is used as reference point for the calculation. The skims are calculated weighted by volume.

Notes

The option is only available with the procedure Calculate dynamic PrT skim matrix.
In this calculation it is important to consider the travel times for the assignment time period in your network. If you are interested in the skims of the margin intervals, make sure that demand exists and that the assignment time period is chosen in such a way that the end of the travel time lies within the analysis time intervals considered.

Example: If the longest travel time in your network is 40 minutes, the assignment time period should start at least 40 minutes before the interval that you want to evaluate. Moreover, demand must already exist at the beginning of the assignment time period.

Output file of a PrT skim matrix

Note: This section is only provided if you would like to save at least one skim matrix to file.

Element	Description
File name	Name of the output skim matrix files. Via the button, you can enter or select the file name (and path, where applicable) for the skim matrix file(s) without file extension(s). Notes If the file name is entered without path, then the file is stored in the pre-set project directory for matrices. Visum adds the file extension according to the Format selected and the settings made under Calculate > General procedure settings > PrT settings > Skims (Setting metadata for skim matrices).
Format	In the list, click the format you want to save the matrices in (Data structures of matrices in Visum-specific text formats). Binary Format V (text format) Format O (text format) Format E (text format) Format S (text format) CSV format (text format)
Separator	Via the selection list you can select the separator to be used for saving the matrices in text format. Notes This selection list is only provided for output in CSV format. For all other formats, spaces are used as separators, so that the matrix can be edited in the matrix editor. Double-click a comma-separated matrix in .csv format to open it as an Excel file. Matrices in .csv format with a different decimal separator must be opened with the Excel Wizard.