libpysal.cg.Chain

class libpysal.cg.Chain(vertices)

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)

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