With the Calculate PrT skim matrix procedure, the PrT skims listed in Table 123 can be calculated (Using Visum: Calculating PrT skims). The abbreviations in parentheses indicate the file extensions which are used by default for skim matrix output in version files.
|
t0-PrTSys (TT0) |
TSys-specific travel time t0 in unloaded network |
|
tCur-PrTSys (TTC) |
TSys-specific travel time tCur in loaded network |
|
AddValue1..3 (AD1 - AD3) |
Sum of AddValue |
|
Trip distance (DIS) |
Distance covered from origin to destination |
|
Direct distance (DID) |
Direct distance between origin and destination zone |
|
Speed v0-PrTSys (VP0) |
TSys-specific speed v0 in unloaded network |
|
Speed vCur-PrTSys (VPC) |
TSys-specific speed vCur in loaded network |
|
Toll (TOL) |
Toll of traversed links |
|
Impedance-PrTSys (IMP) |
TSys-specific impedance in unloaded network |
|
AddValue-TSys (ADS) |
Sum of TSys-AddValue data |
|
User-defined (UDS) |
Flexible calculation of a mean attribute value per OD pair, also allows for the linkage of attributes of different traversed network objects (Using Visum: User-defined PrT skims) |
Calculating skims is either done via the best path as regards to the set criterion or via aggregation from the paths of an assignment result calculated beforehand. In this case you can select one of the aggregation functions listed in Table 124.
|
Minimum impedance |
Skim value calculated from the path with minimum impedance |
|
Maximum impedance |
Skim value calculated from the path with maximum impedance |
|
Mean over paths |
Skim value calculated as a mean over all paths |
|
Mean over path volume |
Skim value calculated as a mean over all paths weighted with the corresponding path volume |
Moreover, the set of origin-destination relations for skims can be calculated, and also restricted like the type of network objects which are included in the skim calculation.
