geo-tz
It takes some time to load and preprocess shapefile, but once it's loaded it's super fast.
Note: both *.shp and *.dbf source files are required.
Installation
npm install @rainder/geo-tz
API
loadShapefile(filepath, options): Promise
options object
{
//uses polygon minification algorithm
//by dropping points in the polygon.
//WARNING: loses geometry precision if used
minify: { //defaults to false
//defines maximum amount of points in the polygon
max_polygon_size: 150,
//precision step in meters
precision_step: 100,
},
//defines geo indexing precision.
//increasing value allows to find timezone faster, but uses more memory
index_precision: 1,
}Usage
Download timezone shape file
$ wget http://efele.net/maps/tz/world/tz_world.zipLoad shape file into the memory
const geoTimezone = require('@rainder/geo-tz')
geoTimezone.loadShapefile('./tz_world.shp').then((tz) => {
const point = {
type: 'Point',
coordinates: [-0.15, 51.5]
};
tz(point); //Europe/London
})