natcap.invest.recreation.out_of_core_quadtree

A hierarchical spatial index for fast culling of points in 2D space.

class natcap.invest.recreation.out_of_core_quadtree.OutOfCoreQuadTree(bounding_box, max_points_per_node, max_node_depth, quad_tree_storage_dir, node_depth=0, node_data_manager=None, pickle_filename=None)

Bases: object

An out of core quad tree spatial indexing structure.

add_points(point_list, left_bound, right_bound)

Add a list of points to the current node.

This function will split the current node if the added points exceed the maximum number of points allowed per node and is already not at the maximum level.

Parameters:

• point_list (numpy.ndarray) – a numpy array of (data, x_coord, y_coord) tuples

• left_bound (int) – left index inclusive of points to consider under point_list

• right_bound (int) – right index non-inclusive of points to consider under point_list

Returns:

None

build_node_shapes(ogr_polygon_layer)

Add features to an ogr.Layer to visualize quadtree segmentation.

Parameters:

ogr_polygon_layer (ogr.layer) – an ogr polygon layer with fields ‘n_points’ (int) and ‘bb_box’ (string) defined.

Returns:

None

flush()

Flush any cached data to disk.

get_intersecting_points_in_bounding_box(bounding_box)

Get list of data that is contained by bounding_box.

This function takes in a bounding box and returns a list of (data, lat, lng) tuples that are contained in the leaf nodes that intersect that bounding box.

Parameters:

bounding_box (list) – of the form [xmin, ymin, xmax, ymax]

Returns:

numpy.ndarray array of (data, x_coord, lng) of nodes that intersect the bounding box.

get_intersecting_points_in_polygon(shapely_polygon)

Return the points contained in shapely_prepared_polygon.

This function is a high performance test routine to return the points contained in the shapely_prepared_polygon that are stored in self’s representation of a quadtree.

Parameters:

shapely_polygon (ogr.DataSource) – a polygon datasource to bound against

Returns:

deque of (data, x_coord, y_coord) of nodes that are contained

in shapely_prepared_polygon.

n_nodes()

Return the number of nodes in the quadtree

n_points()

Return the number of nodes in the quadtree

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