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.</p>
<p>Definitions:</p><dl><dt>Parent</dt>
<dd><p>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 