Using the connection export you create connection files to save computation time during future assignments. You can also import this data in external tools in which you have set up your specific heuristics for the connection choice.
The connection export can be performed with or without volumes. Volumes are required for the connection import procedure. When exporting connections without volumes you can select one of the following options for the export: Connections are to be searched on either all relations or only on those relations with demand > zero.
The option Consider all OD pairs should be used if the demand by relation is not known when the export is performed. Typically this is the case during the PuT skim calculation at the beginning of the Standard-4-step model calculation. Increasing computation time and growing size of the connection file are the disadvantages of this option.
Independently of this option, exported connection files can also store the following data:
- Fare points of the path legs (cannot be imported) and/or
- Fares per path or path leg for a single or all demand segments (can be imported)
- User-defined attribute for PuT paths
For fare calculations in the context of the external choice, the option with fare points has to be enabled since the fare is mostly based on the number of fare points per path leg of the connection.
For connection export without volumes the following assignment parameters are relevant:
- Origin zone interval
- Assignment time period with post-assignment period
- All search parameters
- all parameters for preselection
All other parameters are only effective if an assignment is actually performed, a skim matrix stored or a connection export carried out.
