Isochrone API Tutorial: How to Create an Isochrone Map

Blog post
Niharika Sisodia


    What is an isochrone?

    An isochrone shows reachable areas on a map within a travel time and by a mode of transport. The TravelTime allows you to create isochrones. You can also integrate them into any isochrone app using an API.

    The isochrone API process

    To create an isochrone, the user enters the parameters of their search, including:

    • departure or arrival location
    • mode of transport
    • travel time limit
    • time of the day

    This is a simple JSON request or using settings on your isochrone app. The image below is a client user interface for entering parameters. 


    Once the request is made, the isochrone API receives the request and returns a JSON response. The response includes coordinates for points. These points show the boundaries of shapes reachable within the travel time.

    These results can then be displayed on your isochrone app or a map. The example below shows an isochrone map, which is calculated using our TravelTime API.


     Isochrone maps are a great way to visualise locations you can reach within a certain travel time. The travel time limit for our isochrones is up to 4 hours. Our TravelTime API can also calculate times for up to 100,000 locations by travel time in under 140 ms.

    How do I use this isochrone API?

    The code example below shows how to visualise a travel time response. It shows locations within 1 hour from The White House, Washington DC by public transport. This example uses the TravelTime API and its isochrone algorithm.

    Request an API key

    To make an isochrone, you’ll first need to request a key. You can request an API key for the TravelTime API by clicking here and entering your details.


    Isochrone request and response

    API accepts JSON request and returns a JSON response. 

    The JSON response includes coordinates. These points show the boundaries of shapes reachable within the corresponding travel time. 

    This response has to be visualized on a map. Let’s explore a sample code that could do that.

    Map the response in your isochrone app

    The image above shows how this response would be displayed on a Leaflet map. It can be implemented using any programming language or mapping system you prefer. This is the simplest way to generate a request and display a response using Javascript.

    Let’s break down the code for better understanding.

    First, we need to define parameters for the search. We’ll need to change the name of the start location (The White House) into coordinates using a geocoder. Secondly, we need to change the departure time into the ISO format. Finally, we need to translate the 1 hour travel time into seconds which is 60 minutes x 60 seconds.

    Since this code runs only on the browser we have removed API key from the sample. Like with the JSON request the code must have headers. These headers are needed to authenticate the request and usually sit on the server side of your app.

    For the starting location, we specified The White House. However, the API only accepts coordinates of a location. To change the address into coordinates we use the Geocoder endpoint. The function below sends a request for the geocoder.

    Now that we have everything we need for the request, we can write the code that would generate the request. 

    Finally, we need to call a function to set up a map with a marker at the departure location.

    A separate function is used to draw the multipolygon from the response to reflect the isochrone.

    The full code looks like this: 

    What does this mean for your isochrone app?

    An isochrone API means customers can search for your products and services by time.  For example, Zoopla created an isochrone app using the TravelTime API. This helped their users visualise potential properties. Zoopla has seen an increased conversion rate of 300%.


    Which countries does the isochrone map generator support?

    Sign up for an isochrone API key now and start using The TravelTime API within 24 hours. To learn more about the Travel Time API and isochrone maps, visit our Time Map Resource page.


    Isochrone maps
    Location APIs

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