Finding Optimal Location
Location-allocation modelling is a term used for the identification of optimal locations for a facility in a transport network, in terms of accessibility for people living in the surroundings. This can be used decide optimal locations for a variety of services and different planning, including emergency and public services, retail and commercial services, industrial production and transport planning.
In this project we are going to use Location-allocation to decide the placement of a new school in Tårnby Municipality. To do this, a lot of existing factors are taken into account, such as the existing network and schools, and where the appropriate population is located in the municipality.
A wide variety of data sources are used for this exercise:
- Tables of every resident with age from the CPR-register
- Address table from the BBR-register
- Geometry points for addresses from the BBR-register
- Existing and potential new school locations in Tårnby municipality
- Road network in the municipality
- Paths in the municipality
The objective of this project is to find the best location for a new school in Tårnby municipality taking into account the spatial distribution of 0-6 years old and the location of the existing schools. It is noted that the chosen location should minimize the total school commuting distance for all relevant children in the municipality.
The method we used was to first geocode the addresses and make sure they were attached to the network and that the addresses had the number of residents in the desired age group. Thereafter we ran a New Location-Allocation network analysis to determine the optimal location with the following specifications;
- Facilities = potential school locations
- Demand points = addresses with desired residents
Existing schools were set as required to keep them in place. The Problem Type was set to Maximize Capacitated Coverage. The following results show the best location for a new school.
As the map shows, the best new location for a school will be in the northeastern corner in the municipality. This is also visibly one of the geographically area where the streets are shortest and closest together, indicating that it is a quite built up and therefore more populated area.
The new school is calculated to have 493 students out of a total of 2943 students in the whole municipality.
The network analysis using the Maximize Capacitated Coverage was decided to be the best to use. It took both distance as well as the capacity of the new and existing schools into consideration when deciding on a location. This is also the reason that the school is proposed so close to other schools, since the capacity of some of the old schools is 250, but the number of students in their vicinity is much higher. Furthermore, some of the routing between schools and homes overlap between the different schools, indicating that the analysis perhaps has some problems.
Other Problem Types in the network analysis produced other placements. The Minimize Impedance, which does not consider maximum capacity of existing schools, proposes a location in the south eastern part of the municipality. This type will however only focus on minimizing the total travel times in the municipality. On the map above it shows that some of the travel distances can be quite high for students in the south eastern area. Therefore placing a school in this area and widening the capacity in some of the schools in the northern part may be preferable to placing a new school in the north.