h3-py

Python bindings for the H3 Core Library.

For API reference, see the H3 Documentation.

Installation

From PyPI:

pip install h3

conda config --add channels conda-forge
conda install h3-py

New since v3.6.1: We upload pre-built Python Wheels to PyPI for Linux/Mac/Windows, which should avoid many previous installation issues.

Usage

>>> import h3
>>> lat, lng = 0, 0
>>> resolution = 0
>>> h3.geo_to_h3(lat, lng, resolution)
'8075fffffffffff'

Example gallery

Browse a collection of example notebooks, and if you have examples or visualizations of your own, please feel free to contribute!

We also have a simple walkthrough of the API. For more information, please see the H3 Documentation.

APIs

We provide multiple APIs in h3-py. All APIs have the same set of functions, but differ in their input/output formats.

`h3.api.basic_str`

H3 indexes are represented as Python strs, using list and set for collections.

This is the default API provided when you import h3. That is, import h3.api.basic_str as h3 and import h3 are basically equivalent.

>>> import h3
>>> h = h3.geo_to_h3(0, 0, 0)
>>> h
'8075fffffffffff'

>>> h3.hex_ring(h, 1)
{'8055fffffffffff',
 '8059fffffffffff',
 '807dfffffffffff',
 '8083fffffffffff',
 '8099fffffffffff'}

`h3.api.basic_int`

H3 indexes are represented as Python ints, using list and set for collections.

>>> import h3.api.basic_int as h3
>>> h = h3.geo_to_h3(0, 0, 0)
>>> h
578536630256664575

>>> h3.hex_ring(h, 1)
{577973680303243263,
 578044049047420927,
 578677367745019903,
 578782920861286399,
 579169948954263551}

`h3.api.numpy_int`

H3 indexes are represented as uint64s, using numpy.ndarray for collections.

The intention is for this API to be faster and more memory-efficient by not requiring int to str conversion and by using no-copy numpy arrays instead of Python lists and sets.

>>> import h3.api.numpy_int as h3
>>> h = h3.geo_to_h3(0, 0, 0)
>>> h
578536630256664575

>>> h3.hex_ring(h, 1)
array([578782920861286399, 578044049047420927, 577973680303243263,
       578677367745019903, 579169948954263551], dtype=uint64)

Note that h3 has no runtime dependencies on other libraries, so a standard pip install will install no additional libraries. However, h3.api.numpy_int requires numpy. To have numpy installed (if it isn't already) along with h3, run pip install h3[numpy].

`h3.api.memview_int`

H3 indexes are represented as uint64s, using Python memoryview objects for collections.

This API has the same benefits as numpy_int, except it uses (the less well-known but dependency-free) memoryview.

>>> import h3.api.memview_int as h3
>>> h = h3.geo_to_h3(0, 0, 0)
>>> h
578536630256664575

>>> mv = h3.hex_ring(h, 1)
>>> mv
<MemoryView of 'array' at 0x11188c710>

>>> mv[0]
578782920861286399

>>> list(mv)
[578782920861286399,
 578044049047420927,
 577973680303243263,
 578677367745019903,
 579169948954263551]

When using this API with numpy, note that numpy.array creates a copy of the data, while numpy.asarray does not create a copy and the result points to the same memory location as the memoryview object.

Continuing from the example above,

>>> mv = h3.hex_ring(h, 1)
>>> a = np.array(mv)
>>> mv[0] = 0
>>> a
array([578782920861286399, 578044049047420927, 577973680303243263,
       578677367745019903, 579169948954263551], dtype=uint64)

>>> mv = h3.hex_ring(h, 1)
>>> a = np.asarray(mv)
>>> mv[0] = 0
>>> a
array([                 0, 578044049047420927, 577973680303243263,
       578677367745019903, 579169948954263551], dtype=uint64)

Versioning

h3-py wraps the H3 Core Library, which is written in C. Both projects employ semantic versioning, with versions taking the form X.Y.Z.

h3-py will match the C library in major and minor numbers (X.Y), but may be different on the patch (Z) number.

Use h3.versions() to see the version numbers for both h3-py and the C library. For example,

>>> import h3
>>> h3.versions()
{'c': '3.6.3', 'python': '3.6.1'}

assaflavi / h3-py