Polygon

The Polygon service is used to get travel time polygons starting from a specified source point or a list of source points. The polygons represent the reachable area from a point (or points) of origin within a given travel time. The query can be parameterized by travel times, mode of travel and other parameters in the request options object. The resulting object can be be displayed on a map.

Features

Sources

In order to generate the polygons, one or more source points need to be provided. If you set multiple source points, you have to decide which polygon intersection mode you want to use. Also, you can set the travel mode (walk, bike, car or transit) for each source point individually. The default intersection mode is union, however the polygon service supports three different modes:

Union

The union option means that no intersection of the polygons is performed. We merge the polygons generated on the server side to reduce file size. So each marker has its independent travel time polygons. The colors represent the minimum travel time from any of the given source points.

Intersection

The intersection option generates an intersection of the polygons generated for all source points. This means that no independent polygons exist anymore. The colors represent the maximum travel time from any of the given source points, i.e. the green area is reachable from both source points in 10 minutes.

warningIntersection method is available at plan level basic and above.

Average

The average option generates polygons based on the average travel time for all source points. This means that an individual travel time can be higher than the travel time boundary. The colors represent the average travel time based on the travel times of all given source points.

warningAverage method is available at plan level pro and above.

Please contact us if you want to have a specific intersection method like Kriging, Metaball or kernel density estimation.

Usage

See the different intersection modes in action in this code example!

Travel times

To customize your polygons, you can specify the travel times for which you want to generate polygons. The defaults for this service are walk with polygons for 5 to 30 minutes in 5 minutes steps.

warningPolygon travel times are limited by plan level. Check our plans for details.

Travel types

We provide four different travel types:

Walk & Bike

This returns polygons which indicate the area that is reachable by foot or by bike. The default walking speed is 5 km/h and the default cycling speed is 15 km/h, but you can set these value to your own desired speed. In areas with elevation changes, you can set travel penalties which determine how much the travel speed decreases or increases when walking/cycling up-or-downhill.

Car

This returns polygons which mark the area that is reachable by car. The default travel speed is determined by the speed limits of each individual road, based on data from OpenStreetMaps. This travel type also considers one-way streets, traffic lights and other turning restrictions.

Transit

This returns polygons which mark the area that is reachable by transit. We perform a ‘walk’-routing step from the starting location to the first transit station and from the last transit station to the target location. The transit connections are determined by the GTFS data supplied by the travel agencies of a given area. For this travel type, you can specify the date and time in which a transit connection should be found.

Colors

The colors of the polygons are fully configurable. You can also set inverse polygons, which mask out the unreachable areas, as opposed to coloring the reachable areas.

Default Targomo mode

Color blind mode

High contrast mode

Inverse mode

Minimum polygon hole size

Minimum polygon hole size is the area threshold of a hole inside a polygon which should not be filled with the corresponding polygon color, this is useful if you want to reduce the (file) size of the returned polygon (at the cost of reduced accuracy). This becomes very visible in areas that are not accessible - we may show a park as accessible to cars if it is smaller than the minimum hole size. It makes the polygons less complex, and better looking, but the middle of the park isn’t technically accessible by car. This can be mitigated by modifying the minimum hole size, if accuracy is more important than presentation.

See a code example/ demonstration of the min polygon hole size here!

warningMinimum hole size is limited by plan level. Check our plans for details.