Show HN: Client-side Google Location History visualizer

I built a browser-based tool to visualize Google Location History after they moved Timeline data to on-device storage, making it harder to view your own data.

Demo: https://ethan.dev/utilities/location-history-visualizer

Key features:

• 100% client-side – your data never leaves your browser

• Supports new location-history.json format (from Google Maps app export)

• Also works with older Google Takeout formats (Records.json, Semantic Location History)

• Interactive map with Leaflet.js, customizable styling, PNG export

• No signup, no analytics, no tracking

Technical details:

- Uses Leaflet for mapping, dom-to-image for exports

- Parses multiple Google Timeline formats (they've changed it 3 times)

- Handles the new "geo:lat,lng" coordinate format

- Date range filtering, fullscreen mode, style customization

Why I built this: Google's Timeline migration to on-device storage broke web access. You can export from the Maps app (Settings → Location → Export Timeline data) but there's no easy way to visualize it. This tool runs entirely in your browser with zero server interaction.

The code handles visit objects (places you stayed) and activity objects (routes between locations), showing semantic labels like "Home" and confidence scores.

Open to feedback on the parser logic – Google's format isn't well documented.