VISUM 11.5 Technical details
ICA-Assignment, Blocking Back
We have now implemented an assignment with detailed node impedance directly in VISUM.
The new method is listed as a new variant Assignment with ICA within private transport assignment.
Extended PuT line blocking (including selection of vehicle)
The line blocking feature was completely revised in VISUM 11. With VISUM 11.5 its new functionality is extended in two directions.
Firstly, VISUM now provides a line block viewer that depicts computational results graphically and can even be changed. This block viewer has also been integrated into the graphical Timetable editor (add-on module). In addition to the three modes available so far, the Timetable editor now includes a fourth tab: Block view - PuT line blocks. It displays all blocks of a block version in Gantt charts with a horizontal time axis.
Secondly, the add-on module extended line blocking enhances basic line blocking of the line costing calculation add-on.
- Now vehicle deployment can be further optimized by taking so-called vehicle combination sets into account
- Forced chainings can be modelled as predecessor-successor relations
Complete integration of the new LUCE (Linear User Cost Equilibrium) algorithm
With VISUM 11 we introduced LUCE, a new origin-based gradient method for highway equilibrium assignment. With this new method paths are saved implicitly in data structures called bushes, rather than explicitly as with VISUM’s other assignment methods. This is one of the reasons why LUCE is so performant.
- In VISUM 11.5 we implemented bush-based variants for (nearly) all post-assignment functions.
- Skim matrix calculation (along minimum-cost paths or volume-weighted averages)
- Flow-bundle (select link)
- TFlowFuzzy matrix estimation
- OD pair filter
- Blocking-back model
- Save demand matrix from path volumes
- Path listing, including drawing paths in network view
- COM access to paths
- ANM Route export
- Subnetwork generator
- Demand matrix calibration
- Signal offset optimization
Speeding up computationally intensive procedures through parallelization
VISUM 11.5 now also supports multi-threading for:
- Headway-based public-transport assignment
- PuT line blocking
- Skim matrix calculation
- OD pair filter calculation
- Flow bundle (select link) calculation
With parallelization of the first two procedures VISUM will become a lot faster when you deploy a certain number of processors. For example, the runtime required for a headway-based public transport assignment in a network with 2000 zones and 300 line routes is reduced from 6 min 20 sec on a single core to only 1 min 50 sec on a CPU, using 4 hyperthreaded (= 8 logical) cores.
Extension of TFlowFuzzy matrix estimation
VISUM’s matrix estimator TFlowFuzzy can now handle new types of observed counts. Counts (with tolerances) can now also refer to:
- Flows across screenlines
- Unlinked trips per public transport line
- Boardings / alightings per stop area (optionally including or excluding transfers)
Now TFlowFuzzy can also match a prior or exogenous trip length distribution.
New Scenario manager
The VISUM Scenario manager will support you in managing all your scenario data within a single project. Due to its extensive data volume, the Scenario manager is implemented into VISUM in several steps.
The first one focuses on introducing model-transfer files in a file format that captures the difference between two scenarios of a model in a single ASCII file. Only the minimal base scenario is saved as a version file. All other changes are saved as small deltas that are loaded as model transfer files upon request.
New PuT fare model: Integration of further fare systems
While in Europe there is a prevalence of integrated ticketing across all modes of transport in a geographic area and a single ticket covers the whole journey from door to door, this is less often the case elsewhere.
More typically a metropolitan region is served by many public transport operators, sometimes complementing each other, but often competing. The operators charge fares according to their own fare system. A passenger buys a new ticket each time he boards a vehicle, or at least each time he transfers from one operator to another. Sometimes operators collaborate loosely, granting each other discounted transfers.
In order to model this type of fare system VISUM 11.5 has introduced the concept of a fare system.
POI attributes
With VISUM 11.5 POI categories can optionally inherit user-defined attributes from their parent category. So, if there is the POI category "Building" with the subcategories "Hotel" and "Hospital", you can multi-edit all POIs with a single operation.
Connector attributes for volumes
Links are the network objects that possess the largest number of volume attributes for assignment results. Now connector volumes are also available in disaggregated attributes per DSeg or TSys, so that it is straightforward to apply the right emission factors to all network object volumes throughout the model.
Support of Unicode characters in file names and attribute values
The codes and names of network objects that may appear as subattributes (e.g. DSeg or TSys codes) can now also be written in Unicode format.
This is also true for the file names and paths, since the new File Open/Save dialogs can handle them correctly. This is a huge advantage in cases where the operating system insists on directory names with non-Latin characters.
Advanced options for editing lists
Two new options are now available for editing lists:
- The context menu now provides more commands, including Edit and Delete (provided the underlying object type can be edited or deleted). This will often spare you having to find and highlight a network object in the Network view
- Under Extras – Options – GUI – Lists, you can select Extended input options to use type-specific controls for display and editing
Upgraded Graphics parameters dialog
The new release includes a complete overhaul of the dialog for setting up classifications, an important ingredient for thematic maps.
- Every major graphics parameters page of a network object shows a preview of the network object for each class
- For all point-like and area-like objects the Edit button below the classification grid brings up a new dialog for setting up a new or modifying an existing classification
Redesign and reimplementation of the Matrix editor
One of the biggest improvements realized for demand modeling in VISUM 11.5 is the complete redesign and reimplementation of the Matrix editor. The MUULI successor is fully embedded into VISUM. This produces many benefits:
- All matrices of the current model are displayed in a tree structure. This allows faster access to certain types of matrices (e.g. demand vs. skim matrices)
- Moving the cursor over a tree item will show a ToolTip with summarized information on the matrix. Right-clicking the item brings up a context menu with commands you can apply to the matrix (including opening it in the editor)
- Besides the tabular view, VISUM provides two further views: class shares after classifying the matrix and a scatter plot comparing matrices. Both may remain open during model calibration. This way, you can keep an eye on trip length distribution while fine-tuning the trip distribution parameters
Combining filter conditions
All filter dialogs now allow you to use arbitrary brackets within the filter expression, e.g. "A and (B or C)".
Another handy shortcut is that you can now enter filter conditions of the type A < B (same for <=, >, ...) when A and B are attributes, instead of first having to save the difference A-B as a third attribute.
Digitizing polygon surfaces
Snapping vertices to existing point objects is a great help when you are digitizing polygons. However, sometimes it is difficult to tell whether (and at which point) VISUM will snap, when you release the mouse button. During digitization VISUM 11.5 presents you with a preview of all snappable points in the neighborhood of the cursor that turns into a lasso at the points VISUM would snap, if you released the mouse button right now.
Panning like in VISSIM
By holding the scroll wheel down and dragging the cursor, you can now start the Pan mode, just like in VISSIM!
Advanced printing feature (placeholders / graphics)
The placeholders in the printable area may now also contain graphics instead of only text. This comes in handy, e.g. when you want to print your customer's logo on the corner of a page.
New add-ins
Under the umbrella of the add-in concept that we introduced with the last release, we could add many useful extensions to VISUM over the last year. These are released with the service packs. They self-install under Scripts – VisumAddIn and / or in the Operations dialog under Calculate – Procedure, depending on the type of add-in.
Here we would like to draw your attention to some of the latest add-ins, in case they might have escaped your notice:
Access to further areas of the data model
Via COM you now have access to all areas of the demand data model (matrices, time profiles, activities, demand strata, ...) and the junction model (legs, lanes, lane turns, signal control, ...).
Google Transit import
The Google Transit Feed add-in allows you to import public transport network and timetable data from a Google Transit feed file. Google Transit Feed is an open format used by transit operators to submit their service data to Google’s transit trip planner. You can find a description of the format under: http://code.google.com/transit/spec/transit_feed_specification.html.
Many public transport operators already participate in Google Maps, and if you are building a model for their service area, timetable data may be readily available in Google format.
