How to create a shapely Polygon from a list of shapely Points?

Question

I want to create a polygon from shapely points.

from shapely import geometry
p1 = geometry.Point(0,0)
p2 = geometry.Point(1,0)
p3 = geometry.Point(1,1)
p4 = geometry.Point(0,1)

pointList = [p1, p2, p3, p4, p1]

poly = geometry.Polygon(pointList)

gives me an type error TypeError: object of type 'Point' has no len()

How to create a Polygon from shapely Point objects?

Asked By: Sounak

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Source

Answer 1

The Polygon constructor doesn’t expect a list of Point objects but a list of point coordinates.

See https://shapely.readthedocs.io/en/latest/manual.html#polygons

Answered By: dlask

Answer 2

A Polygon object requires a nested list of numbers, not a list of Point objects.

polygon = Polygon([[0, 0], [1, 0], [1, 1], [0, 1]])

Answered By: Malik Brahimi

Answer 3

If you specifically want to construct your Polygon from the shapely geometry Points, then call their x, y properties in a list comprehension. In other words:

from shapely import geometry

poly = geometry.Polygon([[p.x, p.y] for p in pointList])

print(poly.wkt)  # prints: 'POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))'

Note that shapely is clever enough to close the polygon on your behalf, i.e. you don’t necessarily have to pass-in the first point again at the end.

Answered By: songololo

Answer 4

In version 1.7a2 they have fixed this.

The code in question will just work.

Link to CHANGES.txt

Answered By: Adam

Answer 5

You could just do that instead:

p1 = geometry.Point(0,0)
p2 = geometry.Point(1,0)
p3 = geometry.Point(1,1)
p4 = geometry.Point(0,1)

pointList = [p1, p2, p3, p4]
poly = geometry.Polygon([i for i in pointList])

Answered By: Karantai

How to create a shapely Polygon from a list of shapely Points?

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