inactivist / pytzwhere

python library to look up timezone from lat lng offline

pytzwhere

pytzwhere is a Python library to lookup the timezone for a given lat/lng entirely offline

It is a port from https://github.com/mattbornski/tzwhere with a few improvements.

If used as a library, basic usage is as follows:

>>> import tzwhere
>>> tz = tzwhere.tzwhere()
Reading json input file: tz_world_compact.json
>>> print tz.tzNameAt(35.29, -89.66)
America/Chicago

By default (and as shown above), the tzwhere class (at the heart of this library) initialises itself from a JSON file. Note that this is very very memory hungry (about 750MB, though the file is much smaller). You can save a lot of memory (hundred of megabytes) at the cost of another second or so initialisation time, by telling tzwhere to read its data in (one line at a time) from a CSV file instead:

>>> tz = tzwhere.tzwhere(input_kind='csv')
Reading from CSV input file: tz_world.csv
>>> print tz.tzNameAt(35.29, -89.66)
America/Chicago

The module can also be run as a script, which offers some other possibilities including producing the CSV file mentioned above. Instructions and usage information can be seen by running:

tzwhere.py --help

Dependencies (both optional):

• docopt - if you want to use tzwhere.py as a script (e.g. as shown above).

• numpy - if you want to save about 200MB of RAM.