You make some basic settings for the line construction.
1. Make sure the Construct lines window is open (Construct lines automatically).
2. If necessary, select an existing parameter set for the line construction from the Preselect a parameter set selection list (Creating a procedure parameter set).
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Note: You can save a modified or new parameter set before the calculation, i.e. after you have clicked OK. The following possibilities are provided:
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Note: You can check your network to see whether it is suitable for automatic line construction (Checking the network). |
3. Edit the desired settings on the Basis tab.
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Element |
Description |
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Basic setting of the calculation |
Construct only lines If this option is selected, a line pool is constructed. There is no selection of lines or calculation of the headway. This option is useful if you want to check your line construction settings first and correct any existing network errors. Calculate headways If this option is selected, the existing lines in the network are used, to which a headway from the selected regular service pattern is assigned based on the demand. Construct lines and calculate headways If this option is selected, a line pool is constructed and selected lines are provided with headways according to the specified regular service pattern. |
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Headways |
From the drop-down list, you can select the desired regular service pattern for the calculation. |
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Fixed lines section |
In the following, the existing supply that is used by the procedure is defined, but it is not changed. Selection attribute for lines with a fixed course and headway: If you have selected one of the options for calculating lines, you can select an attribute that identifies lines with a fixed course and headway. The attribute value of the selected line must not be zero. Headway attribute for lines with a fixed course and headway If you have selected a selection attribute for lines with a fixed course and headway, you must also select a headway attribute that identifies lines with a fixed headway. Selection attribute for lines with a fixed course If you have selected an option for line construction, you can select a line attribute that identifies lines with a fixed course. The attribute value of the selected line must not be zero. |
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Iterations section |
Maximum number of iterations Here, specify the maximum number of iterations after which the procedure ends if no convergence occurs. Number of iterations without improvement As convergence criterion, enter the number of iterations, after which the solution must be improved to iterate further. Number of solutions per iteration The higher the number of solutions which are determined per iteration, the higher the quality of the result to be expected. Note Both the time required for the calculation and the required memory capacity will increase in this case, however. |
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Save parameters / Open parameters |
Using the buttons you can save your settings in an *.lcx file or open saved settings. Note The buttons are only displayed if you have opened the line construction via the Calculate > Construct lines menu and use the line construction independently of scenario management. |
Transport systems tab
You can define separate settings for each transport system in the table.
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Element |
Description |
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Build line routes for transport system column |
Selection of transport systems in the open network for which line routes are constructed. |
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Capacity of a vehicle column |
Capacity of a typical vehicle in the transport system |
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Number of available vehicles column |
Optional, number of vehicles to be used for lines of the transport system |
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Attribute for terminal stop points column |
Selection of the attribute for the terminal stop points at which lines may start and end. The attribute value of the selected terminal stop points must not be equal to zero. |
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Maximum detour factor |
The detour factors are important for determining which line routes are considered useful for line construction. Value for the maximum detour factor that is required if, for example, local detours have to be taken into account for which a larger detour is required to avoid larger obstacles. |
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Minimum detour factor |
Value for the global detour factor, used for longer distances. The higher the value, the less direct a line route may be between the start and end stop points. |
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Minimum operational layover time |
Value in minutes that defines the minimum layover time at the end stop point |
Assignment tab
Taking demand into account is crucial for the creation and evaluation of the line concepts (Fundamentals: Demand).
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Element |
Description |
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Demand segments |
Selection of the considered demand segments |
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Demand period section |
From / To You specify the demand period via the input fields. Demand is considered to be equally distributed. If the network has a calendar, you can also set the start and end day. |
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Competing journey time of another mode section |
Journey time matrix for the competition (in minutes): Select a journey time matrix for a competing mode. On relations where the adjusted journey time of the competing mode is lower, no connections are constructed. Demand on these relations is ignored (Fundamentals: Taking existing transport supply into account). |
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Factor for the competition journey time |
Factor for the evaluation of journey times in the competing mode |
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Additive constant for the competition journey time |
In addition to the factor, you can add a fixed value in minutes to the competition journey time. |
Objective function tab
On this tab, you determine the weight of each single component of the objective function (Fundamentals: Structure of the base model).
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Element |
Description |
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Weights of the objective function components section |
In each row, this column contains a cost component of the objective function. The individual components of the objective function are described here: (Fundamentals: Overview of the procedure) |
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Factor |
In this column, you can enter a factor for each component after double-clicking the respective row. This way, you specify the weight with which the component enters the objective function. |
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Weight |
This column outputs the automatically determined share of the total weight 100% for each user-defined factor. |
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Minimum number of services per hour |
This option is only displayed if a weight greater than 0 is specified for the minimum and maximum service level component. Selection of a stop point attribute that contains the minimum number of services. |
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Maximum number of services per hour |
This option is only displayed if a weight greater than 0 is specified for the minimum and maximum service level component. Selection of a stop point attribute that contains the maximum number of services. |
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Expected number of variable lines (budget) |
Approximate number of lines to be generated in the new network. A high number of lines promotes direct trips, but is more difficult to implement operationally. Solutions with more lines are rated negatively in this component. |
Output section
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Element |
Description |
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Attribute for the calculated headway |
Specification of the attribute in which the headways are saved. The public transport supply results from lines with a headway in this attribute. |
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Number of good solutions issued |
Number of desired solutions. The best solution and the maximum network, which contains all specified and constructed lines, are always output. |
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Output extreme solutions found (Pareto-Optima) |
If this option is selected, solutions that are optimal in an objective component are also output. These solutions show what value an objective component can assume in extreme cases if the other objective components are neglected (Pareto-Optima). |
4. Click OK to start the line construction.
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Note: You can save a modified or new parameter set before the calculation, i.e. after you have clicked OK. The following possibilities are provided:
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Once the calculation is complete, the solutions of the line construction are listed as new scenarios on the Scenarios tab and there is an associated modification for each new scenario on the Modifications tab.
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Note: If the line construction was started outside the scenario management via the menu Calculate > Construct lines, the results are saved as model transfer files. |
