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

verticeslist – Point 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