This is a library for timezone lookup by latitude and longitude. It uses a bounding box to check the most likely polygons with a more accurate winding number algorithm. We need both speed and highly accurate results and this is the resulting project.

1. Speed
2. Accuracy.
3. Easy.
4. Concurrent safe.
5. Easy updating of zip file locally.

    go get github.com/catmullet/tz

    make updategeo

*The script will delete the current tzdata.snappy compiled TimeZone file and Download a new geojson zip file. This new geojson file will be loaded and compiled on the next run or by running unit tests. A new tzdata.snappy file will be created.

Copy the tzdata.snappy file to the package you are going to initialize the time zone lookup object.

    lookup, err := tz.NewGeoJsonTimeZoneLookup("timezones-with-oceans.geojson.zip")
    // OR
    // export GEO_JSON_FILE="path/timezones-with-oceans.geojson.zip" or will pull from root directory
    lookup, err := tz.NewGeoJsonTimeZoneLookup("")
    // OR Get info from logging
    lookup, err := tz.NewGeoJsonTimeZoneLookup("", os.Stderr)

Parse by Lat Lon and return string value of time zone.

    timeZone := lookup.TimeZone(5.261417, -3.925778)

Parse for time.Location.

    var ti = time.Now()
    
    var loc, _ = lookup.Location(5.261417, -3.925778)
    
    // Set time to location from lookup, easy!
    ti.In(loc).Zone()

Tests performed with cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz