On the one hand, the arrangement of the elements in the schematic line diagram is based on the selection of transfer nodes and vehicle journeys. On the other hand, it is optimized and adjusted to your needs by manual modifications. In many cases, a suitable arrangement shall be used for other variants and timetable updates. If they were linked to the data structures in the data model, manual modifications would be lost as soon as an edge course disappeared from the schematic line diagram, e.g. due to the selection of a different aggregation level, a modification of the vehicle journey selection, or changes to or even replacements of timetable data (e.g. due to data import for a new timetable period). To retain a manually edited layout of the schematic line diagram despite such modifications and transfer the layout to other supply variants in other version files, the following mechanisms are provided. Besides automatically saving parameters in the version file, you can separately save all parameters to files and reload them, which allows you to easily transfer the layout and graphic parameters to other version files. The settings are saved in two kinds of files. The graphic parameters file contains all purely graphic settings regarding colors, bars and so on. The layout file contains the settings regarding selected transfer nodes and vehicle journeys and their positions and courses as well as the information on the allocation of vehicle journeys to edge courses. In the schematic line diagram, the allocation of vehicle journeys to edge courses is not controlled by the actual key attribute (i.e. the vehicle journey number) but, depending on the selected aggregation level, via a set of identifying attributes. In the layout parameters window (Using Visum: Setting the layout for schematic line diagrams), these attributes are listed in the field Identification attribute for unused edge courses. When editing the timetable data or the layout parameters (for example the vehicle journey selection), the vehicle journeys are reallocated to the edge courses based on these attributes, new edge courses are created, if necessary, existing ones are hidden and the graphic display is adjusted. Even for hidden edge courses the layout parameters will not be lost, i.e. Visum "remembers" that there used to be an edge course for line A between transfer node 123 and 987 with a manually adjusted course, even if the edge is not displayed any more. This information is used again when requesting an edge course with the same key once more. You can, however, explicitly empty this "memory" of the schematic line diagram.
The dynamic allocation of vehicle journeys to edge courses and the preservation of the layout information on hidden edge courses allows you to retain a display despite of changes to or a complete exchange of the timetable data (with deviating vehicle journey numbers) and use it on other supply variants. In particular, this mechanism allows the use of the schematic line diagram together with the scenario management, when, for example, creating a line diagram with the desired layout in the base version which will then be automatically adjusted to the data of the scenario when opening scenario results.
