# libpysal.cg.Chain¶

class libpysal.cg.Chain(vertices)[source]

Geometric representation of a chain, also known as a polyline.

Attributes
verticeslist

Returns the vertices of the chain in clockwise order.

lenfloat

Returns the geometric length of the chain.

__init__(self, vertices)[source]

Returns a chain created from the points specified.

__init__(Point list or list of Point lists) -> Chain

Parameters
verticeslistPoint list or list of Point lists.

Examples

>>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])


Methods

 __init__(self, vertices) Returns a chain created from the points specified.

Attributes

 arclen Returns the geometric length of the chain computed using arcdistance (meters). bounding_box Returns the bounding box of the chain. len Returns the geometric length of the chain. parts Returns the parts of the chain. segments Returns the segments that compose the Chain vertices Returns the vertices of the chain in clockwise order.
property arclen

Returns the geometric length of the chain computed using arcdistance (meters).

len -> number

property bounding_box

Returns the bounding box of the chain.

bounding_box -> Rectangle

Examples

>>> c = Chain([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1))])
>>> c.bounding_box.left
0.0
>>> c.bounding_box.lower
0.0
>>> c.bounding_box.right
2.0
>>> c.bounding_box.upper
1.0

property len

Returns the geometric length of the chain.

len -> number

Examples

>>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])
>>> c.len
3.0
>>> c = Chain([[Point((0, 0)), Point((1, 0)), Point((1, 1))],[Point((10,10)),Point((11,10)),Point((11,11))]])
>>> c.len
4.0

property parts

Returns the parts of the chain.

parts -> Point list

Examples

>>> c = Chain([[Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))],[Point((2,1)),Point((2,2)),Point((1,2)),Point((1,1))]])
>>> len(c.parts)
2

property segments

Returns the segments that compose the Chain

property vertices

Returns the vertices of the chain in clockwise order.

vertices -> Point list

Examples

>>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])
>>> verts = c.vertices
>>> len(verts)
4