Any number of zones may be combined to form a main zone. The zones themselves remain. There are OD pairs between all main zones of the network. The zone matrices (demand matrices and skim matrices) can be aggregated to main zone matrices if desired. Likewise, main zones can be broken down to zones. The same function is available for main zone matrices, as for zone matrices. As an option, main zone boundaries (polygons) can be defined.
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Note: Main zone boundaries are managed (The surface data model in Visum) like surfaces and can be made up of multi-face polygons or polygons with "holes". |
Use cases for the application of main zones arise in the following situations:
- Multiple zones can be aggregated to larger study areas in very detailed modeled networks. This often also makes the graphical display in the network editor clearer.
- Display of flow bundles on main zone level
- Display of desire lines
If you connect multiple zones to one main zone, you can make the desire lines clearer.
- Executing diverse procedures on main zone level
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Note: It is currently not possible to calculate assignments or demand models on main zone level. |
