Chris Essig

Walkthroughs, tips and tricks from a data journalist in eastern Iowa

Archive for December 2016

Leaflet formula: Counting markers within a radius (version 2)

with 2 comments

A couple of years ago, I open-sourced a project that allows you to count how many markers are within a circle using Leaflet. As part of the template, a user needs to enter an address to get a marker to show up on the map.

Two weeks ago, Jefferson Guerrón reached out to me because he was creating something similar that didn’t require a user to type in their address. He was using the plugin Leaflet.draw to get the marker on the map. But he was having a hard time getting a circle to show up around the marker and count the other markers within that circle.

After a few back-and-forth emails, we were able to come up with a solution. Here’s a look of the final project. And the code is available on Github.

If you have questions, don’t hesitate to e-mail or comment.

Written by csessig

December 14, 2016 at 5:15 pm