libpysal.cg.Grid¶

class libpysal.cg.Grid(bounds, resolution)[source]¶

Representation of a binning data structure.

Create a grid with the specified bounds and resolution.

Parameters:¶

bounds : Rectangle¶: The area for the grid to encompass.
resolution : number¶: The diameter of each bin.

Examples

TODO: complete this doctest >>> g = Grid(Rectangle(0, 0, 10, 10), 1)

Methods

`add`(item, pt)	Adds an item to the grid at a specified location.
`bounds`(bounds)	Returns a list of items found in the grid within the bounds specified.
`in_grid`(loc)	Returns whether a 2-tuple location _loc_ lies inside the grid bounds.
`nearest`(pt)	Returns the nearest item to a point.
`proximity`(pt, r)	Returns a list of items found in the grid within a specified distance of a point.
`remove`(item, pt)	Removes an item from the grid at a specified location.

add(item, pt)[source]¶

Adds an item to the grid at a specified location.

add(x, Point) -> x

Parameters:¶

item : the item to insert into the grid¶
pt : the location to insert the item at¶

Examples

>>> g = Grid(Rectangle(0, 0, 10, 10), 1)
>>> g.add('A', Point((4.2, 8.7)))
'A'

bounds(bounds)[source]¶

Returns a list of items found in the grid within the bounds specified.

bounds(Rectangle) -> x list

Parameters:¶

bounds : Rectangle¶: Bounding box used to query items stored in the grid.

Examples

>>> g = Grid(Rectangle(0, 0, 10, 10), 1)
>>> g.add('A', Point((1.0, 1.0)))
'A'
>>> g.add('B', Point((4.0, 4.0)))
'B'
>>> g.bounds(Rectangle(0, 0, 3, 3))
['A']
>>> g.bounds(Rectangle(2, 2, 5, 5))
['B']
>>> sorted(g.bounds(Rectangle(0, 0, 5, 5)))
['A', 'B']

in_grid(loc)[source]¶

Returns whether a 2-tuple location _loc_ lies inside the grid bounds.

Test tag: <tc>#is#Grid.in_grid</tc>

nearest(pt)[source]¶

Returns the nearest item to a point.

nearest(Point) -> x

Parameters:¶

pt : the location to search near¶

Examples

>>> g = Grid(Rectangle(0, 0, 10, 10), 1)
>>> g.add('A', Point((1.0, 1.0)))
'A'
>>> g.add('B', Point((4.0, 4.0)))
'B'
>>> g.nearest(Point((2.0, 1.0)))
'A'
>>> g.nearest(Point((7.0, 5.0)))
'B'

proximity(pt, r)[source]¶

Returns a list of items found in the grid within a specified distance of a point.

proximity(Point, number) -> x list

Parameters:¶

pt : the location to search around¶
r : the distance to search around the point¶

Examples

>>> g = Grid(Rectangle(0, 0, 10, 10), 1)
>>> g.add('A', Point((1.0, 1.0)))
'A'
>>> g.add('B', Point((4.0, 4.0)))
'B'
>>> g.proximity(Point((2.0, 1.0)), 2)
['A']
>>> g.proximity(Point((6.0, 5.0)), 3.0)
['B']
>>> sorted(g.proximity(Point((4.0, 1.0)), 4.0))
['A', 'B']

remove(item, pt)[source]¶

Removes an item from the grid at a specified location.

remove(x, Point) -> x

Parameters:¶

item : the item to remove from the grid¶
pt : the location the item was added at¶

Examples

>>> g = Grid(Rectangle(0, 0, 10, 10), 1)
>>> g.add('A', Point((4.2, 8.7)))
'A'
>>> g.remove('A', Point((4.2, 8.7)))
'A'