Selectors

To optimize response time and size, by default, the MVT and JSON API return a minimized response. This approach ensures peak performance and reduces tile payload sizes, which is critical for smooth map interactions. By using selectors, you can include the additional data points your application specifically requires.

Where to use

  • Station Features Only: Selectors are only applicable to station features (count: 1). They do not affect the properties of cluster features.
  • MVT and JSON endpoints only: Selectors can be used in both the MVT and JSON endpoints, but not in the count endpoint.

Available selectors

Any field listed in the station properties for MVT and JSON tiles can be used as a selector in its respective service, with the exception of the mandatory GeoJSON fields returned in JSON endpoint.

Implementation

To request specific properties, append station_properties[] query parameter to the tile request URL.

Behaviour Examples

When selectors are provided, the request returns only the specified fields.

GeoJSON

In the GeoJSON endpoint, the mandatory GeoJSON fields (type and geometry and id ) are always returned regardless of the selectors chosen.

MVT

In MVT endpoint, only the parameters explicitly selected are returned as there are no mandatory fields.