What is an Isochrone?

An isochrone refers to the visualization that delineates areas with equivalent travel times or equidistance from a designated point of origin. These areas are graphically represented on maps, illustrating the time required to reach various destinations starting from a central reference point.

Key Components of Isochrone

  1. Central Point: Isochrones emanate from a focal point, typically a specific location, and extend outward. The selection of this central point is often based on the user’s present position or a point of interest.
  2. Time Intervals: Isochrones are traditionally constructed using defined time intervals, outlining regions that can be accessed within a specified duration. For instance, an isochrone map may delineate zones reachable within 15, 30, and 60 minutes from the central reference point.
  3. Mode of Travel: Isochrones can be customized for different modes of transportation, like walking, two-wheelers, cars, trucks, etc. The chosen mode influences the size and configuration of the isochrone areas due to variations in travel speeds.

Applications of Isochrones

Isochrones serve a diverse array of applications in various domains, including:

Location-Based Services: Isochrone maps are invaluable for location-based services, providing users with insights into travel times to nearby amenities, businesses, or services.

Urban Planning: Urban planners employ isochrones to assess accessibility and transportation options, assisting in the formulation of transportation networks and city layouts.

Emergency Services: Emergency responders use isochrones to gauge response times and strategize efficient resource allocation to incidents.

Business Location Analysis: Corporations leverage isochrones to evaluate potential business sites based on their proximity to customers, suppliers, and employees.

Tourism and Real Estate: Isochrone maps assist tourists and real estate buyers in comprehending the proximity of attractions, services, and neighborhoods to a chosen location.

What does an isochrone map mean?

You can see on an isochrone map what areas you can get to in a certain amount of time or distance. You might think that an isochrone map looks like a sphere with the starting point in the middle, but that isn’t always the case. Different factors, such as speed limits, traffic, and the way roads wind, can make isochrone maps look different.

When making isochrone maps, these factors are used to figure out what area a person can reach in a certain amount of time. Isochrones make maps of temporal proximity that are much more accurate than simple distance-radius maps because they use travel time instead of distance.

Why would you want to use an isochrone map?

In most places, you can’t go in all directions at the same time. Two ends may be only five miles apart, but getting to one of them might take a lot longer. This is because of things other than just distance, like geography, traffic, and the routes that different types of transportation can take, like train tracks, bike paths, and ski slopes.

Isochrone maps use these factors to figure out what areas can be reached in a certain amount of time. This lets people or businesses accurately plan for commutes, delivery times, or other important travel metrics.

How Isochrone Maps Work


Let’s look at an example. Let’s say a company is thinking about where in Seattle to put its new factory. They know they want the factory to be on the edge of town, but they don’t want it to be too far from the people who live downtown and work there. 

An employee who lives ten miles away in the suburbs might only need fifteen minutes to get to work, but an employee who lives in downtown Seattle might need thirty minutes to get the same distance. Ten miles in the city can take a lot longer than ten miles in the suburbs because there are more cars, stoplights, and other things that can slow people down.

With the help of an isochrone map, a company can figure out how long it will take employees from different parts of the municipality to get to work. This includes traffic jams, busy bridges, and natural features like Seattle’s many water features.

There are seven ways to use isochrone maps

1. Choosing a Site

Isochrone maps help find the best places for new businesses like stores and offices by drawing catchment areas based on how easy they are to get to. When businesses combine isochrones with population data, they learn more about the people who might become customers. Isochrones are used by real estate analytics companies like Watson + Homes to find the best places to invest and define travel time areas.

2. Planning for public transportation

Isochrones help plan public transportation by showing where transit doesn’t work well. TravelTime API can make public transportation isochrones to show areas that aren’t well served, like transit blackspots or places that need better road networks. For instance, research might show that travel times could be cut by optimizing routes between places like Brighton and Petworth.

3. A plan for marketing

Isochrones help businesses see where their customers are likely to shop and plan more effective marketing campaigns. IKEA, for example, used a 20-minute drive-time isochrone map to find the best places to advertise in their local area. By focusing on customers who are traveling during certain times, this method improves proximity marketing strategies.

4. Planning your sales territory

By assigning sales territories based on travel times, isochrone maps help make sales territory planning more efficient. This helps sales teams get in touch with customers faster and helps companies find areas that aren’t being served well enough. Thomas Sanderson uses isochrones to make sure that his field staff covers all the bases and that customers get better service by letting them focus on the areas that need more work.

5. Optimizing your property search

Property websites use isochrones to help people find homes that are close to their preferred work hours and ways to get to work. Zoopla, for example, uses isochrone maps to show all the homes that are within a certain travel time. This makes the experience better for users and boosts conversion rates.

6. Search for Employees

Recruiters use isochrone maps to focus on certain areas when hiring for jobs, especially those that need people to be close to a location. If a new call center opens, isochrones can help find the best places to hire people by looking at how long it takes them to get to work.

7. Improvements to the travel search

Travel websites use isochrones to help people find attractions, hotels, and other interesting places based on their preferred travel times and modes of transportation. This helps users plan trips more efficiently by focusing on places to go that can be reached in the time frames that users want.

These ways of using isochrone maps can help people in many fields make better decisions, plan better, and market their products more effectively.

What are the limitations of isochrone maps?

Isochrone maps have several limitations. They focus solely on travel time, not distance, so they won’t track the distance covered—use an isodistance map for that purpose. Additionally, while isochrone maps show possible routes, they may not highlight the optimal route.

Another limitation is the variability of drive times. Isochrone maps can be less reliable when planning trips in advance due to fluctuating traffic conditions. Real-time traffic data, such as that provided by Google Maps, can help, but it may not reflect future traffic patterns accurately. For instance, the drive time between the Eiffel Tower and Notre-Dame Cathedral in Paris can vary significantly depending on the day and time, like Sunday afternoon versus Wednesday at 5 pm.

Understanding these limitations helps in making informed decisions when using isochrone maps for planning.

Creating Isochrone Maps

Isochrone maps are crafted using Geographic Information Systems (GIS) and location data. GIS software computes travel times from the central point, considering factors like road networks, terrain, and the chosen mode of travel. The resulting isochrone areas are then depicted on maps, with varying colors or shades indicating distinct time intervals.

In conclusion, isochrones are effective tools for determining travel time and accessibility, making them indispensable for informed decision-making across domains such as urban planning, transportation, and location-based services. They provide clear visual representations of travel time, allowing for more informed decisions and resource allocation.

Explore NextBillion.ai’s Isochrone API for more details.