python-geojson¶

This 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

Installation
GeoJSON Objects
GeoJSON encoding/decoding
- Custom classes
Helpful utilities
- coords
- map_coords
Development
Credits

Installation¶

python-geojson is compatible with Python 2.6, 2.7, 3.2, 3.3, and 3.4. It is listed on PyPi as ‘geojson’. The recommended way to install is via pip:

pip install geojson

GeoJSON Objects¶

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

Point¶

>>> from geojson import Point

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

Visualize the result of the example above here. General information about Point can be found in Section 2.1.2 and Appendix A: Point within The GeoJSON Format Specification.

MultiPoint¶

>>> from geojson import MultiPoint

>>> MultiPoint([(-155.52, 19.61), (-156.22, 20.74), (-157.97, 21.46)])  
{"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 2.1.3 and Appendix A: MultiPoint within The GeoJSON Format Specification.

LineString¶

>>> from geojson import LineString

>>> LineString([(8.919, 44.4074), (8.923, 44.4075)])  
{"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 2.1.4 and Appendix A: LineString within The GeoJSON Format Specification.

MultiLineString¶

>>> 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)]
... ])  
{"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 2.1.5 and Appendix A: MultiLineString within The GeoJSON Format Specification.

Polygon¶

>>> from geojson import Polygon

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

>>> # hole within polygon
>>> Polygon([
...     [(2.38, 57.322), (23.194, -20.28), (-120.43, 19.15), (2.38, 57.322)],
...     [(-5.21, 23.51), (15.21, -10.81), (-20.51, 1.51), (-5.21, 23.51)]
... ])  
{"coordinates": [[[2.3..., 57.32...], [23.19..., -20.2...], [-120.4..., 19.1...]], [[-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 2.1.6 and Appendix A: Polygon within The GeoJSON Format Specification.

MultiPolygon¶

>>> 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)],)
... ])  
{"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 2.1.7 and Appendix A: MultiPolygon within The GeoJSON Format Specification.

GeometryCollection¶

>>> from geojson import GeometryCollection, Point, LineString

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

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

>>> GeometryCollection([my_point, my_line])  
{"geometries": [{"coordinates": [23.53..., -63.1...], "type": "Point"}, {"coordinates": [[-152.6..., 51.2...], [5.2..., 10.6...]], "type": "LineString"}], "type": "GeometryCollection"}

Visualize the result of the example above here. General information about GeometryCollection can be found in Section 2.1.8 and Appendix A: GeometryCollection within The GeoJSON Format Specification.

Feature¶

>>> from geojson import Feature, Point

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

>>> Feature(geometry=my_point)  
{"geometry": {"coordinates": [-3.68..., 40.4...], "type": "Point"}, "id": null, "properties": {}, "type": "Feature"}

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

>>> Feature(geometry=my_point, id=27)  
{"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 2.2 within The GeoJSON Format Specification.

FeatureCollection¶

>>> 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)))

>>> FeatureCollection([my_feature, my_other_feature])  
{"features": [{"geometry": {"coordinates": [1.643..., -19.12...], "type": "Point"}, "id": null, "properties": {}, "type": "Feature"}, {"geometry": {"coordinates": [-80.23..., -22.53...], "type": "Point"}, "id": null, "properties": {}, "type": "Feature"}], "type": "FeatureCollection"}

Visualize the result of the example above here. General information about FeatureCollection can be found in Section 2.3 within The GeoJSON Format Specification.

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.

>>> import geojson

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

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

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

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

>>> geojson.loads(dump)  
{"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.

>>> 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)  
'{"coordinates": [52.23..., -19.23...], "type": "Point"}'

Helpful utilities¶

coords¶

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

>>> 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))  
[(-152.62..., 51.21...), (5.21..., 10.69...)]

map_coords¶

geojson.utils.map_coords maps a function over all coordinate tuples and returns a geometry of the same type. Useful for translating a geometry in space or flipping coordinate order.

>>> 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)  
'{"coordinates": [-57.905..., 18.62...], "type": "Point"}'

Development¶

To build this project, run python setup.py build. To run the unit tests, run python setup.py test.

Credits¶

Sean Gillies <sgillies@frii.com>
Matthew Russell <matt@sanoodi.com>
Corey Farwell <coreyf@rwell.org>