Mapping latitude and longitude to country, state, or city
a year ago
- #javascript
- #geocoding
- #maps
- Reverse geocoding converts latitude and longitude coordinates to readable locations like country, state, or city.
- The author created a client-side JavaScript library called coord2state to determine US states from coordinates, avoiding costly APIs like Google Maps.
- The library uses simplified US state border data from the US Census Bureau, reducing vertices significantly while maintaining 99.9% accuracy.
- Simplification with the Douglas-Peucker algorithm reduces file size; a 0.01° tolerance results in a 260 KB minified library.
- Accuracy tests show that small drops in precision lead to significant reductions in file size, making the library practical for client-side use.
- Edge cases, such as points near borders or in gaps between simplified borders, require additional handling.
- The library is available on GitHub and NPM as coord2state.