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Objective of Optimisation

The Route Optimisation service aims at finding a good plan for the given transport. In order to determine what "good" means here, two questions need to be answered:

The way these questions are answered can be controlled by the user.

What makes one plan better than another?

Default objective

The default objective comprises four criteria in the following order.

  1. The first criterion is to have a plan where every transport is planned in a route. This means a plan with all transports planned is always considered as better than a plan with unplanned transport, no matter what the other KPIs are. But sometimes, there are just too many transports and not all of them can be planned. In this case, we distinguish the standard case from the priorities case:
    1. Standard case: A plan with the least unplanned transports is considered as best.
    2. Priorities case: This is the case when the query parameter considerTransportPriorities is set to true and all transport is ranked by priority. When comparing two plans, the plan with fewer unplanned transport of priority x is best, where x is the highest priority in which the number of unplanned transports differs between the two plans. See the transport priorities concept page for more details.
  2. By default, the second criterion is to use as few vehicles as possible or, in other words, to create as few routes as possible. This default behaviour can be adjusted. By adding IGNORE_MINIMISATION_OF_NUMBER_OF_ROUTES to tweaksToObjective, this criterion is skipped.
  3. By default, the third criterion is to create as few trips as possible. This default behaviour can be adjusted. By adding IGNORE_MINIMISATION_OF_NUMBER_OF_ROUTES to tweaksToObjective, this criterion is skipped.
  4. By default, the fourth criterion is to minimise the distance, driving time and travel time of each route. To be precise, a linear combination of these values is minimised.

Tweaks to objective

tweaksToObjective is a query parameter. There are two non-exclusive options:

  • When routes are drawn onto a map by drawing straight lines between two consecutive stops, these lines may intersect each other. Some extra effort is spent on avoiding these intersections. However, a plan calculated with AVOID_INTERSECTIONS enabled may be worse than a plan calculated with AVOID_INTERSECTIONS disabled.
  • IGNORE_MINIMISATION_OF_NUMBER_OF_ROUTES suppresses criteria 2 and 3 of the default objective (as described in paragraph Default objective above).

How much effort should be put into finding a better plan?

The more time is spent on optimisation, the higher the chances of finding a better plan. There is a trade-off between the solution quality and the running time of the optimisation. This trade-off can be adjusted via two query parameters.

Optimisation quality

There is a standard setting of the trade-off between solution quality and running time. With the query parameter quality, the user can set this to HIGH and put the solution quality in favour of running time.

Enhanced feature set

The query parameter optimisationPremium unleashes some more algorithmic features that can improve the solution quality but come at the cost of a higher running time. See the Optimisation Premium concept page for more details.