tzgeo

tzgeo is a Python library with one simple purpose - to convert a lat/lon to a timezone - really fast!

Installation

The easiest way to install is using pip

pip install tzgeo

If you're lucky, this will install okay.

tzgeo relies on the pyspatialite library, and unfortunately that can be a little difficult to install. If the installation of pyspatialite fails, try running:

pip install pyspatialite --pre
pip install tzgeo

... and see if that works.

Usage

Using tzgeo is very simple!

>>> import tzgeo
>>> tzgeo.tz_lookup(39.888724, -75.107952)
u'America/New_York'

If the lat/lon is invalid, or points at the ocean, tz_lookup will return None.

>>> print(tzgeo.tz_lookup(0.0, 0.0))
None

How Is This Done?

tzgeo includes a sqlite/spatialite database containing the the geographical regions that make up each timezone. The data was obtained from whereonearth-timezone.

spatialite provides the ability to do fast lookup to see whether a polygon contains a given point, so lookups in this database are pretty fast. The underlying storage is also reasonable efficient, so the database is only ~35Mb.

Are There Any Alternatives?

I wrote this to be a faster alternative to tzwhere. tzwhere is much easier to install, because it has no external dependencies. If speed isn't your main concern, that may be a better option.

You Did Something Wrong!

If you have any problems installing or using the library, please create an issue describing the problem you're having, along with any information you think might be useful.

I'm not a GIS expert, so I may have made a mistake. If you can suggest improvements, please let me know. Even better, submit a pull request with a fix!

Todo

• Region limiting, for faster lookups, e.g. tz_lookup(lat, lon, 'America') (This might make it faster, who knows?)
• Decide whether to calculate a timezone based on longitude if the location is in the sea.