[crazygringo]

No, it is clearly not as the pigeon flies. That is incorrect.

When I click on my local subway stop it seems entirely accurate, and the stations don't form any kind of circle at all. In fact I can't find any subway stop origin that seems to form anything even close to a circle.

Also, according to the "about" it's calculating from actual subway schedules.

And it has nothing to do with street grids. It's subway trips, not walking.

[crote]

Nah, GP is right.

The station-to-station part does indeed use subway travel times, but the website says "Hover over a station to see how much of the city is accessible within 40 minutes by subway and walking."

And the "walking" part clearly shows a perfect circle around each destination station, so it is 100% doing an as-the-pigeon-flies estimation for the walking.

[bentaber]

From the About

"Isochrones are manually calculated using turf.js assuming 1.2m/s walking speed after the subway trip. These are simple buffers around each station/prior isochrone and do not take the street network into account."

[parpfish]

The “pigeon flies” part is about the circles that form around each station to reflect walking time after you leave the train.

[xsmasher]

Parent poster is referring to the walking segments; the walking bubble around each station is a circle.

Click on Rockaway park. A pigeon could reach those islands, but a walking person could not.

This is still a great visualization.

[IIAOPSW]

Other people already corrected you, but I feel like being obtuse so here it goes. The circle goes from Jamaica, along Queens Blvd, down 8th Ave to W 4th St, along the F line to Jay St, down Fulton St to Broadway Junction, past Cypress hills on the Nassau line (J/Z), and finally returns to Jamaica. This loop is possible without adding any additional tracks or switches to the system. Thats how the pigeon flies. Checkmate.

[tantalor]

> not walking

The site says "accessible within 40 minutes by subway and walking"