pygeoif 1.6.0

Introduction

PyGeoIf provides a GeoJSON-like protocol for geo-spatial (GIS) vector data.

Other Python programs and packages that you may have heard of that implement this protocol:

• ArcPy

• descartes

• PySAL

• Shapely

• pyshp

• GeoPandas

• Karta

• mapnik

When you want to write your own geospatial library with support for this protocol you may use pygeoif as a starting point and build your functionality on top of it. It has no requirements outside the Python standard library and is therefore easy to integrate into your project. It is tested on CPython, PyPy and GraalPy, but it should work on alternative Python implementations (that implement the language specification >=3.9) as well.

You may think of pygeoif as a ‘shapely ultralight’ which lets you construct geometries and perform very basic operations like reading and writing geometries from/to WKT, constructing line strings out of points, polygons from linear rings, multi polygons from polygons, etc. It was inspired by shapely and implements the geometries in a way that when you are familiar with pygeoif, you will feel right at home with shapely or the other way round. It provides Hypothesis strategies for all geometries for property based testing with Hypothesis.

It was written to provide clean and python only geometries for fastkml

pip install pygeoif

Example

>>> from pygeoif import geometry
>>> p = geometry.Point(1,1)
>>> p.__geo_interface__
{'type': 'Point', 'bbox': (1, 1, 1, 1), 'coordinates': (1, 1)}
>>> print(p)
POINT (1 1)
>>> p
Point(1, 1)
>>> l = geometry.LineString([(0.0, 0.0), (1.0, 1.0)])
>>> l.bounds
(0.0, 0.0, 1.0, 1.0)
>>> print(l)
LINESTRING (0.0 0.0, 1.0 1.0)

You find more examples in the tests directory which cover every aspect of pygeoif or in fastkml.

Classes

All classes implement the attribute:

• __geo_interface__: as discussed above, an interface to GeoJSON.

All geometry classes implement the attributes:

• geom_type: Returns a string specifying the Geometry Type of the object

• bounds: Returns a (minx, miny, maxx, maxy) tuple that bounds the object.

• wkt: Returns the ‘Well Known Text’ representation of the object

For two-dimensional geometries the following methods are implemented:

• convex_hull: Returns a representation of the smallest convex Polygon containing all the points in the object unless the number of points in the object is less than three. For two points, the convex hull collapses to a LineString; for 1, a Point. For three dimensional objects only their projection in the xy plane is taken into consideration. Empty objects without coordinates return None for the convex_hull.

>>> from pygeoif import geometry
>>> p = geometry.Point(1.0, -1.0)
>>> p2 = geometry.Point(1.0, -1.0)
>>> geoms = [p, p2]
>>> c = geometry.GeometryCollection(geoms)
>>> [geom for geom in geoms]
[Point(1.0, -1.0), Point(1.0, -1.0)]

>>> from pygeoif import Point, Feature
>>> p = Point(1.0, -1.0)
>>> props = {'Name': 'Sample Point', 'Other': 'Other Data'}
>>> a = Feature(p, props)
>>> a.properties
{'Name': 'Sample Point', 'Other': 'Other Data'}
>>> a.properties['Name']
'Sample Point'

>>> from pygeoif import Point, Feature, FeatureCollection
>>> p = Point(1.0, -1.0)
>>> props = {'Name': 'Sample Point', 'Other': 'Other Data'}
>>> a = Feature(p, props)
>>> p2 = Point(1.0, -1.0)
>>> props2 = {'Name': 'Sample Point2', 'Other': 'Other Data2'}
>>> b = Feature(p2, props2)
>>> features = [a, b]
>>> c = FeatureCollection(features)
>>> [feature for feature in c]
[Feature(Point(1.0, -1.0), {'Name': 'Sample Point', 'Other': 'Other Data'},...]

Functions

>>> from shapely.geometry import Point
>>> from pygeoif import geometry, shape
>>> shape(Point(0,0))
Point(0.0, 0.0)

>>> from pygeoif import from_wkt
>>> p = from_wkt('POINT (0 1)')
>>> print(p)
POINT (0.0 1.0)

Development

Clone this repository, create a virtualenv with Python 3.8 or later with python3 -m venv .venv and activate it with source .venv/bin/activate.

Then install the requirements with pip install -e ".[dev]".

pip install pre-commit
pre-commit install

pre-commit run --all-files

pytest tests
pytest --doctest-glob="README.rst"
ruff check pygeoif
ruff fmt pygeoif
mypy pygeoif

Acknowledgments

The tests were improved with mutmut which discovered some nasty edge cases.