osbng (version 0.2.0)

bng_to_children: Navigate the British National Grid hierarchy

Description

Identify the "parent" or "children" references which contain or are nested within a given BNG reference.

Usage

bng_to_children(bng_ref, resolution, ...)
bng_to_parent(bng_ref, resolution, ...)

Value

child references will be a list of BNGReference objects with each item in the list being the set of children for the input grid reference. Parent references will be a vector of BNGReference

objects.

Arguments

bng_ref

object of type BNGReference

resolution

(optional) value of the target resolution of parent/child references. If omitted, the next resolution relative to the input BNG reference is assumed.

...

additional parameters. Not currently used

Details

The BNG is structured using a hierarchical system of grid squares at various resolutions. At its highest level, the grid divides GB into 100 km by 100 km squares, each identified by a two-letter code. Successive levels of resolution further subdivide the grid squares into finer detail, down to individual 1-meter squares. These functions allow for the traversal of this hierarchy by providing methods to return the parent and children of BNGReference objects at specified resolutions.

Definitions:

Parent

The parent of a BNGReference object is the grid square at the next higher (coarser) resolution level that contains the current reference. For example, the parent of a 1km grid square reference would be the 5km grid square that contains it.

Children

The children of a BNGReference object are the grid squares at the next lower (finer) resolution level that are contained within the current reference. For example, the children of a 10km grid square reference would be all the 5km grid squares that it contains.

Examples

bng_to_children(as_bng_reference("SU"))

bng_to_children(as_bng_reference("SU36"))

bng_to_parent(as_bng_reference("SU36SW"))

bng_to_parent(as_bng_reference("SU342567"))

bng_to_parent(as_bng_reference("SU342567"), resolution = 10000)