Show service areas for multiple facilities

Find the service areas of several facilities from a feature service.

Use case

A city taxi company may calculate service areas around their vehicle lots to identify gaps in coverage. Alternatively, they may want to ensure overlaps where a high volume of passengers requires redundant facilities, such as near an airport.

How to use the sample

Upon running, the sample will calculate and display the service area of each facility (hospital) on the map. The polygons displayed around each facility represents the facility’s service area: the red area is within 1 minute travel time from the hospital by car, whilst orange is within 3 minutes by car. All service areas are semi-transparent to show where they overlap.

How it works

1. Create a new ServiceAreaTask from a network service.
2. Create default ServiceAreaParameters from the service area task.
3. Set the parameters returnsPolygons property to true to return polygons of all service areas.
4. Define QueryParameters that retrieve all features from the facilities FeatureTable. Add the facilities to the service area parameters using the query parameters, serviceAreaParameters.setFacilities(fromFeaturesIn:queryParameters:)
5. Get the ServiceAreaResult by solving the service area task using the parameters.
6. For each facility, get any ServiceAreaPolygons that were returned, ServiceAreaResult.resultPolygons(forFacilityAtIndex:).
7. Display each service area polygon as a Graphic in a GraphicsOverlay on the MapView.

Relevant API

• ServiceAreaParameters
• ServiceAreaPolygon
• ServiceAreaResult
• ServiceAreaTask

About the data

This sample uses a street map of San Diego, in combination with a feature service with facilities (used here to represent hospitals). Additionally a street network is used on the server for calculating the service area.

Tags

facilities, feature service, impedance, network analysis, service area, travel time