Welcome to centerline’s documentation!

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Roads, rivers and similar linear structures are often represented by long and complex polygons. Since one of the most important attributes of a linear structure is its length, extracting that attribute from a polygon can prove to be more or less difficult.

This library tries to solve this problem by creating the the polygon’s centerline using the Voronoi diagram.

_images/example.png

The source and the output geometry visualized in QGIS.

Features

  • A command-line script for creating centerlines from a vector source file and saving them into a destination vector file: create_centerlines

$ create_centerlines input.shp output.geojson
  • The Centerline class that allows integration into your own workflow.

>>> from shapely.geometry import Polygon
>>> from centerline.geometry import Centerline

>>> polygon = Polygon([[0, 0], [0, 4], [4, 4], [4, 0]])
>>> attributes = {"id": 1, "name": "polygon", "valid": True}

>>> centerline = Centerline(polygon, **attributes)
>>> centerline.id == 1
True
>>> centerline.name
'polygon'
>>> centerline.geoms
<shapely.geometry.base.GeometrySequence object at 0x7f7d24116210>

Indices and tables