County Maps US

Tools Map makers and file viewers

Map Drawer

A sketchpad on a real map. Every line you draw reports its length and every shape its area, and your work stays in the browser between visits.

How to use it

  1. Pick a tool: Line, Polygon, Freehand, Arrow or Text, and a colour and width.
  2. Click the map to add points, then double-click or press Finish. For freehand, press and drag. For an arrow, click the tail then the head.
  3. Use Select to click a shape, then Delete to remove it. Undo and redo cover the last fifty changes.
  4. Export the drawing as GeoJSON, or as a PNG snapshot of the map.

How it works

Lengths are great-circle distances summed along each line and areas are spherical polygon areas, both computed in the browser from the coordinates you drew. Nothing about your drawing is sent to a server.

The drawing is saved in your browser's local storage after every change and restored on your next visit on the same device. The PNG export captures the WebGL map canvas; some browsers block that capture, in which case the tool says so and the GeoJSON export still works.

Questions

Will my drawing still be there tomorrow?
On the same browser and device, yes: it is autosaved to local storage. It is not synced anywhere, so another device or a private window starts empty. Export GeoJSON to keep a copy.
How accurate are the distances?
They are great-circle distances on a sphere of mean Earth radius, accurate to about 0.3 percent, which is closer than most people can click.
Can I load a drawing back in?
Not into this tool yet. The GeoJSON export opens in the GeoJSON viewer on this site and in most GIS software.

All map tools, free and without an account. Location data is processed in your browser and by the open geocoding services named on the sources page; nothing is stored by this site.