Try it: draw a chapter map from counts

This is the working version of the chapter map tutorial. Paste one row per chapter (a name, a state, a latitude, a longitude and a member count), choose a minimum count, and the lab draws the map, hides every chapter below the minimum and gives you the file you would publish. The example is a fictional association with eight chapters.

Chapter table (counts only, one row per chapter)

Hide chapters with fewer than members

Five is a working choice, not a standard. Pick the number your privacy lead is comfortable with.

Add the OpenStreetMap basemap

Off, the map itself contacts no other website. On, your browser asks the OpenStreetMap Foundation's tile servers for map pictures, which tells them your IP address and that this page asked. Your chapter table is never part of those requests.

What would be published

Chapter	State	Members shown

Travel ring around a meeting

Meeting in within miles

Distances are straight lines over the earth's surface, not driving or flight routes.

How this lab works

Counts in, a safe file out. Each row becomes one point. A chapter below your minimum is published with no count and a hidden flag, so the downloaded file never holds the small number.
Five columns only. Chapter name, state, latitude, longitude and members. Anything else, including a name, an email address or a street address, is refused.
Edit and the result goes stale. Change the table or the minimum and the download button switches off until you draw again, so the file always matches what is on screen.
Local files only. The state outlines come from this site, and Leaflet is served from this site too, so nothing loads from a content network.
Looks right in light and dark mode. The map repaints when you toggle the theme.

Starter kit

The starter kit holds the finished static page (index.html and app.js), the example chapter table and its published file, simplified state outlines, a copy of Leaflet with its license, and a pre-publish checklist. Free with your email through the form below; the download link appears after you subscribe.