geojson

Python bindings and utilities for GeoJSON

https://github.com/jazzband/geojson

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Python bindings and utilities for GeoJSON

README.rst

geojson
==============

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This Python library contains:

- Functions for encoding and decoding GeoJSON_ formatted data
- Classes for all GeoJSON Objects
- An implementation of the Python `__geo_interface__ Specification`_

**Table of Contents**

.. contents::
   :backlinks: none
   :local:

Installation
------------

geojson is compatible with Python 3.7 - 3.13. The recommended way to install is via pip_:

.. code::

  pip install geojson

.. _PyPi as 'geojson': https://pypi.python.org/pypi/geojson/
.. _pip: https://www.pip-installer.org

GeoJSON Objects
---------------

This library implements all the `GeoJSON Objects`_ described in `The GeoJSON Format Specification`_.

.. _GeoJSON Objects: https://tools.ietf.org/html/rfc7946#section-3

All object keys can also be used as attributes.

The objects contained in GeometryCollection and FeatureCollection can be indexed directly.

Point
~~~~~

.. code:: python

  >>> from geojson import Point

  >>> Point((-115.81, 37.24))  # doctest: +ELLIPSIS
  {"coordinates": [-115.8..., 37.2...], "type": "Point"}

Visualize the result of the example above `here `__. General information about Point can be found in `Section 3.1.2`_ and `Appendix A: Points`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.2: https://tools.ietf.org/html/rfc7946#section-3.1.2
.. _Appendix A\: Points: https://tools.ietf.org/html/rfc7946#appendix-A.1

MultiPoint
~~~~~~~~~~

.. code:: python

  >>> from geojson import MultiPoint

  >>> MultiPoint([(-155.52, 19.61), (-156.22, 20.74), (-157.97, 21.46)])  # doctest: +ELLIPSIS
  {"coordinates": [[-155.5..., 19.6...], [-156.2..., 20.7...], [-157.9..., 21.4...]], "type": "MultiPoint"}

Visualize the result of the example above `here `__. General information about MultiPoint can be found in `Section 3.1.3`_ and `Appendix A: MultiPoints`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.3: https://tools.ietf.org/html/rfc7946#section-3.1.3
.. _Appendix A\: MultiPoints: https://tools.ietf.org/html/rfc7946#appendix-A.4


LineString
~~~~~~~~~~

.. code:: python

  >>> from geojson import LineString

  >>> LineString([(8.919, 44.4074), (8.923, 44.4075)])  # doctest: +ELLIPSIS
  {"coordinates": [[8.91..., 44.407...], [8.92..., 44.407...]], "type": "LineString"}

Visualize the result of the example above `here `__. General information about LineString can be found in `Section 3.1.4`_ and `Appendix A: LineStrings`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.4: https://tools.ietf.org/html/rfc7946#section-3.1.4
.. _Appendix A\: LineStrings: https://tools.ietf.org/html/rfc7946#appendix-A.2

MultiLineString
~~~~~~~~~~~~~~~

.. code:: python

  >>> from geojson import MultiLineString

  >>> MultiLineString([
  ...     [(3.75, 9.25), (-130.95, 1.52)],
  ...     [(23.15, -34.25), (-1.35, -4.65), (3.45, 77.95)]
  ... ])  # doctest: +ELLIPSIS
  {"coordinates": [[[3.7..., 9.2...], [-130.9..., 1.52...]], [[23.1..., -34.2...], [-1.3..., -4.6...], [3.4..., 77.9...]]], "type": "MultiLineString"}

Visualize the result of the example above `here `__. General information about MultiLineString can be found in `Section 3.1.5`_ and `Appendix A: MultiLineStrings`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.5: https://tools.ietf.org/html/rfc7946#section-3.1.5
.. _Appendix A\: MultiLineStrings: https://tools.ietf.org/html/rfc7946#appendix-A.5

Polygon
~~~~~~~

.. code:: python

  >>> from geojson import Polygon

  >>> # no hole within polygon
  >>> Polygon([[(2.38, 57.322), (-120.43, 19.15), (23.194, -20.28), (2.38, 57.322)]])  # doctest: +ELLIPSIS
  {"coordinates": [[[2.3..., 57.32...], [-120.4..., 19.1...], [23.19..., -20.2...]]], "type": "Polygon"}

  >>> # hole within polygon
  >>> Polygon([
  ...     [(2.38, 57.322), (-120.43, 19.15), (23.194, -20.28), (2.38, 57.322)],
  ...     [(-5.21, 23.51), (15.21, -10.81), (-20.51, 1.51), (-5.21, 23.51)]
  ... ])  # doctest: +ELLIPSIS
  {"coordinates": [[[2.3..., 57.32...], [-120.4..., 19.1...], [23.19..., -20.2...]], [[-5.2..., 23.5...], [15.2..., -10.8...], [-20.5..., 1.5...], [-5.2..., 23.5...]]], "type": "Polygon"}

Visualize the results of the example above `here `__. General information about Polygon can be found in `Section 3.1.6`_ and `Appendix A: Polygons`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.6: https://tools.ietf.org/html/rfc7946#section-3.1.6
.. _Appendix A\: Polygons: https://tools.ietf.org/html/rfc7946#appendix-A.3

MultiPolygon
~~~~~~~~~~~~

.. code:: python

  >>> from geojson import MultiPolygon

  >>> MultiPolygon([
  ...     ([(3.78, 9.28), (-130.91, 1.52), (35.12, 72.234), (3.78, 9.28)],),
  ...     ([(23.18, -34.29), (-1.31, -4.61), (3.41, 77.91), (23.18, -34.29)],)
  ... ])  # doctest: +ELLIPSIS
  {"coordinates": [[[[3.7..., 9.2...], [-130.9..., 1.5...], [35.1..., 72.23...]]], [[[23.1..., -34.2...], [-1.3..., -4.6...], [3.4..., 77.9...]]]], "type": "MultiPolygon"}

Visualize the result of the example above `here `__. General information about MultiPolygon can be found in `Section 3.1.7`_ and `Appendix A: MultiPolygons`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.7: https://tools.ietf.org/html/rfc7946#section-3.1.7
.. _Appendix A\: MultiPolygons: https://tools.ietf.org/html/rfc7946#appendix-A.6

GeometryCollection
~~~~~~~~~~~~~~~~~~

.. code:: python

  >>> from geojson import GeometryCollection, Point, LineString

  >>> my_point = Point((23.532, -63.12))

  >>> my_line = LineString([(-152.62, 51.21), (5.21, 10.69)])

  >>> geo_collection = GeometryCollection([my_point, my_line])

  >>> geo_collection  # doctest: +ELLIPSIS
  {"geometries": [{"coordinates": [23.53..., -63.1...], "type": "Point"}, {"coordinates": [[-152.6..., 51.2...], [5.2..., 10.6...]], "type": "LineString"}], "type": "GeometryCollection"}

  >>> geo_collection[1]
  {"coordinates": [[-152.62, 51.21], [5.21, 10.69]], "type": "LineString"}

  >>> geo_collection[0] == geo_collection.geometries[0]
  True

Visualize the result of the example above `here `__. General information about GeometryCollection can be found in `Section 3.1.8`_ and `Appendix A: GeometryCollections`_ within `The GeoJSON Format Specification`_.

.. _Section 3.1.8: https://tools.ietf.org/html/rfc7946#section-3.1.8
.. _Appendix A\: GeometryCollections: https://tools.ietf.org/html/rfc7946#appendix-A.7

Feature
~~~~~~~

.. code:: python

  >>> from geojson import Feature, Point

  >>> my_point = Point((-3.68, 40.41))

  >>> Feature(geometry=my_point)  # doctest: +ELLIPSIS
  {"geometry": {"coordinates": [-3.68..., 40.4...], "type": "Point"}, "properties": {}, "type": "Feature"}

  >>> Feature(geometry=my_point, properties={"country": "Spain"})  # doctest: +ELLIPSIS
  {"geometry": {"coordinates": [-3.68..., 40.4...], "type": "Point"}, "properties": {"country": "Spain"}, "type": "Feature"}

  >>> Feature(geometry=my_point, id=27)  # doctest: +ELLIPSIS
  {"geometry": {"coordinates": [-3.68..., 40.4...], "type": "Point"}, "id": 27, "properties": {}, "type": "Feature"}

Visualize the results of the examples above `here `__. General information about Feature can be found in `Section 3.2`_ within `The GeoJSON Format Specification`_.

.. _Section 3.2: https://tools.ietf.org/html/rfc7946#section-3.2

FeatureCollection
~~~~~~~~~~~~~~~~~

.. code:: python

  >>> from geojson import Feature, Point, FeatureCollection

  >>> my_feature = Feature(geometry=Point((1.6432, -19.123)))

  >>> my_other_feature = Feature(geometry=Point((-80.234, -22.532)))

  >>> feature_collection = FeatureCollection([my_feature, my_other_feature])

  >>> feature_collection # doctest: +ELLIPSIS
  {"features": [{"geometry": {"coordinates": [1.643..., -19.12...], "type": "Point"}, "properties": {}, "type": "Feature"}, {"geometry": {"coordinates": [-80.23..., -22.53...], "type": "Point"}, "properties": {}, "type": "Feature"}], "type": "FeatureCollection"}

  >>> feature_collection.errors()
  []

  >>> (feature_collection[0] == feature_collection['features'][0], feature_collection[1] == my_other_feature)
  (True, True)

Visualize the result of the example above `here `__. General information about FeatureCollection can be found in `Section 3.3`_ within `The GeoJSON Format Specification`_.

.. _Section 3.3: https://tools.ietf.org/html/rfc7946#section-3.3

GeoJSON encoding/decoding
-------------------------

All of the GeoJSON Objects implemented in this library can be encoded and decoded into raw GeoJSON with the ``geojson.dump``, ``geojson.dumps``, ``geojson.load``, and ``geojson.loads`` functions. Note that each of these functions is a wrapper around the core `json` function with the same name, and will pass through any additional arguments. This allows you to control the JSON formatting or parsing behavior with the underlying core `json` functions.

.. code:: python

  >>> import geojson

  >>> my_point = geojson.Point((43.24, -1.532))

  >>> my_point  # doctest: +ELLIPSIS
  {"coordinates": [43.2..., -1.53...], "type": "Point"}

  >>> dump = geojson.dumps(my_point, sort_keys=True)

  >>> dump  # doctest: +ELLIPSIS
  '{"coordinates": [43.2..., -1.53...], "type": "Point"}'

  >>> geojson.loads(dump)  # doctest: +ELLIPSIS
  {"coordinates": [43.2..., -1.53...], "type": "Point"}

Custom classes
~~~~~~~~~~~~~~

This encoding/decoding functionality shown in the previous can be extended to custom classes using the interface described by the `__geo_interface__ Specification`_.

.. code:: python

  >>> import geojson

  >>> class MyPoint():
  ...     def __init__(self, x, y):
  ...         self.x = x
  ...         self.y = y
  ...
  ...     @property
  ...     def __geo_interface__(self):
  ...         return {'type': 'Point', 'coordinates': (self.x, self.y)}

  >>> point_instance = MyPoint(52.235, -19.234)

  >>> geojson.dumps(point_instance, sort_keys=True)  # doctest: +ELLIPSIS
  '{"coordinates": [52.23..., -19.23...], "type": "Point"}'

Default and custom precision
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

GeoJSON Object-based classes in this package have an additional `precision` attribute which rounds off
coordinates to 6 decimal places (roughly 0.1 meters) by default and can be customized per object instance.

.. code:: python

  >>> from geojson import Point

  >>> Point((-115.123412341234, 37.123412341234))  # rounded to 6 decimal places by default
  {"coordinates": [-115.123412, 37.123412], "type": "Point"}

  >>> Point((-115.12341234, 37.12341234), precision=8)  # rounded to 8 decimal places
  {"coordinates": [-115.12341234, 37.12341234], "type": "Point"}


Precision can be set at the package level by setting `geojson.geometry.DEFAULT_PRECISION`


.. code:: python

  >>> import geojson

  >>> geojson.geometry.DEFAULT_PRECISION = 5

  >>> from geojson import Point

  >>> Point((-115.12341234, 37.12341234))  # rounded to 8 decimal places
  {"coordinates": [-115.12341, 37.12341], "type": "Point"}


After setting the DEFAULT_PRECISION, coordinates will be rounded off to that precision with `geojson.load` or `geojson.loads`. Following one of those with `geojson.dump` is a quick and easy way to scale down the precision of excessively precise, arbitrarily-sized GeoJSON data.


Helpful utilities
-----------------

coords
~~~~~~

:code:`geojson.utils.coords` yields all coordinate tuples from a geometry or feature object.

.. code:: python

  >>> import geojson

  >>> my_line = LineString([(-152.62, 51.21), (5.21, 10.69)])

  >>> my_feature = geojson.Feature(geometry=my_line)

  >>> list(geojson.utils.coords(my_feature))  # doctest: +ELLIPSIS
  [(-152.62..., 51.21...), (5.21..., 10.69...)]

map_coords
~~~~~~~~~~

:code:`geojson.utils.map_coords` maps a function over all coordinate values and returns a geometry of the same type. Useful for scaling a geometry.

.. code:: python

  >>> import geojson

  >>> new_point = geojson.utils.map_coords(lambda x: x/2, geojson.Point((-115.81, 37.24)))

  >>> geojson.dumps(new_point, sort_keys=True)  # doctest: +ELLIPSIS
  '{"coordinates": [-57.905..., 18.62...], "type": "Point"}'

map_tuples
~~~~~~~~~~

:code:`geojson.utils.map_tuples` maps a function over all coordinates and returns a geometry of the same type. Useful for changing coordinate order or applying coordinate transforms.

.. code:: python

  >>> import geojson

  >>> new_point = geojson.utils.map_tuples(lambda c: (c[1], c[0]), geojson.Point((-115.81, 37.24)))

  >>> geojson.dumps(new_point, sort_keys=True)  # doctest: +ELLIPSIS
  '{"coordinates": [37.24..., -115.81], "type": "Point"}'

map_geometries
~~~~~~~~~~~~~~

:code:`geojson.utils.map_geometries` maps a function over each geometry in the input.

.. code:: python

  >>> import geojson

  >>> new_point = geojson.utils.map_geometries(lambda g: geojson.MultiPoint([g["coordinates"]]), geojson.GeometryCollection([geojson.Point((-115.81, 37.24))]))

  >>> geojson.dumps(new_point, sort_keys=True)
  '{"geometries": [{"coordinates": [[-115.81, 37.24]], "type": "MultiPoint"}], "type": "GeometryCollection"}'

validation
~~~~~~~~~~

:code:`is_valid` property provides simple validation of GeoJSON objects.

.. code:: python

  >>> import geojson

  >>> obj = geojson.Point((-3.68,40.41,25.14,10.34))
  >>> obj.is_valid
  False

:code:`errors` method provides collection of errors when validation GeoJSON objects.

.. code:: python

  >>> import geojson

  >>> obj = geojson.Point((-3.68,40.41,25.14,10.34))
  >>> obj.errors()
  'a position must have exactly 2 or 3 values'

generate_random
~~~~~~~~~~~~~~~

:code:`geojson.utils.generate_random` yields a geometry type with random data

.. code:: python

  >>> import geojson

  >>> geojson.utils.generate_random("LineString")  # doctest: +ELLIPSIS
  {"coordinates": [...], "type": "LineString"}

  >>> geojson.utils.generate_random("Polygon")  # doctest: +ELLIPSIS
  {"coordinates": [...], "type": "Polygon"}


Development
-----------

To build this project, run :code:`python setup.py build`.
To run the unit tests, run :code:`python -m pip install tox && tox`.
To run the style checks, run :code:`flake8` (install `flake8` if needed).

Credits
-------

* Sean Gillies 
* Matthew Russell 
* Corey Farwell 
* Blake Grotewold 
* Zsolt Ero 
* Sergey Romanov 
* Ray Riga 


.. _GeoJSON: https://geojson.org/
.. _The GeoJSON Format Specification: https://tools.ietf.org/html/rfc7946
.. _\_\_geo\_interface\_\_ Specification: https://gist.github.com/sgillies/2217756

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