onyx is a slippy map tool with annotation capabilities built using leaflet and written in typescript. It can be used to catalogue skate spots, document forage, record routes, or anything else that map overlay data would be useful for.

All data from onyx is stored in the browser's localStorage, and the only network calls are those to fetch tile data and, if you opt in, for initial geolocation to set your home point. Data can be imported or exported in JSON format, allowing easy sharing of data via email, file share, etc.

Currently, the basic features are all in place but the UI could use some expansion (like editing path data or moving markers and circles) and some polish to the click handling code could decrease memory usage.