World map and crop
Open a Java world folder to get a top-down map like BlueMap, click any chunk for its data, then cut out the rectangle you need and clean the world up before handing it over. Everything runs in your browser: the world is never uploaded, not even in parts.
Drop a world folder or a .zip here
or
Java Anvil · 1.8 → 26.x · region/ · entities/ · poi/ · DIM-1 · DIM1 · dimensions/
The world is read from your disk region by region and never sent anywhere.
This browser does not let sites write to folders: the map and chunk data work, and a cropped world is given back as a .zip up to ~1 GB. Large worlds need Chrome, Edge or Opera.
Wheel — zoom · drag — move · Shift+drag — select chunks · click — chunk data