Recently I made a few base maps of various-sized buffers around ad hoc points. This type of request is quite common from my colleagues - draw a circle around a given point to understand relationships of distance.

I thought to myself - there must be a tool which allows one to drop a point on a map and see arbitrary distances, and to simply visualize these.

What I came up with is a basic workflow: using two tools together which harness the versatility of JavaScript object notation (GeoJSON) and the relative simplicity of tools which parse it:

GitHub Gists supports rendering GeoJSON in the browser.


  1. Spatial data
  2. Buffer calculation and visualization
  3. Map styles


  1. - allows for in-browser data editing and
  2. - built on the capability of turf.js and engineered by the folks at CUGOS, Dropchop is an in-browser GIS.
  3. Mapbox styles