A radius or a drive time? Choosing the area around a site

Use a radius (a plain circle) when you want a quick, even measure to compare many sites, or when the area is dense and walkable in every direction. Use a travel time or a distance by road when rivers, motorways, rail lines or one-way systems mean that the nearest people are not the ones who can reach you most easily. A circle answers "what is near"; a travel area answers "what can actually get here".

This article is for people who draw areas around sites for a living or for a decision: expansion teams, franchise planners, logistics managers, analysts preparing a site report. It sets out what each shape measures, the cases where each one wins, a worked comparison, and how to use either in xMap Flows.

What each shape measures

The radius

A circle of, say, 1 km around a site includes everything whose straight-line distance is under 1 km. It ignores roads entirely. Its strengths are that it is quick, the same everywhere, easy to explain, and fair for ranking a long list: every site gets exactly the same ground to work with. Many standard figures are circles. xMap's market pages, for instance, count places within 10 km of a city's centre; for London that circle holds 1,367 bakeries, and of the 380 nearest the centre, 121 belong to a chain (xMap's places database, November 2026).

The travel area

A travel area follows the network. "15 minutes by car" stretches along fast roads and shrinks where streets are slow or blocked. "2 km by road" is the ground you can cover along streets in 2 km, which is always smaller than a 2 km circle, because roads wind. On foot or by bike the shape changes again: footbridges count, motorways do not. The Travel area block draws these shapes by car, on foot or by bike, as a travel time or a distance by road.

When the circle is the right choice

• Comparing dozens or hundreds of candidate sites to make a shortlist.
• Dense, gridded centres where you can walk in any direction.
• Very short distances, such as 500 m for a corner shop, where the road network hardly changes the answer.
• Reports that must match a published method, such as market sizing within a set distance.
• Anything you will repeat in many countries, where you want the measure to stay identical.

When the travel area is worth it

• Sites near a river, a railway, a motorway or the coast. A circle happily includes homes on the far bank that have no bridge for miles.
• Destinations people drive to: supermarkets, clinics, warehouses, car services. Ten minutes by car is how they think.
• Delivery and service areas, where a van's real reach decides the promise you can make.
• Comparing a suburban site with a central one. A 3 km circle is a short drive in the suburbs and a long one downtown.
• Shortlists, after the circle has done the first sort. Spend the extra care on the final few.

A worked comparison

A made-up case. A clinic group in Paris weighs two sites and wants to know how many people live near each. With a 1 km circle, the figures (invented here) are close: 31,000 residents around Site A and 29,500 around Site B. With a 15-minute walk instead, Site B reaches far fewer, 18,000, because a rail corridor and a ring road cut off its east side; Site A, on an open grid of streets, still reaches 27,000. The circle said the sites were equal. The walking area says Site A serves half as many people again.

The lesson is not that circles are wrong. They found two sites worth comparing in the first place. The travel area settled the choice between them.

Choosing the size

Whatever the shape, size it to how people use what you offer. A rough guide to start from, to adjust with your own knowledge:

Starting points, not rules; the right size depends on the city and the customer.

Doing it in xMap Flows

Both shapes plug into the same blocks: whatever comes after them searches inside the area.

1. Bring in your sites with My data, or type them into the Travel area block under Places I pick.
2. For a circle, set the distance in each data block (Within, on Demographics or Nearby places).
3. For a travel area, add Travel area first: choose a travel time or a distance by road, and car, walking or cycling. Set the next blocks' Where to Automatic.
4. Add Demographics for residents, Nearby places for rivals, or both, then send the result by email.

Every place found inside a travel area carries its name, for example "15 minutes by car of the Camden store", so each manager reads their own part. Ready-made versions: Rivals within 10 minutes' drive of each store, Who my warehouse reaches in 15 minutes, for same-day delivery, and Who and what is within a 15-minute walk of a planned station.