Administrative boundary alignments

Administrative boundaries may or may not have a predefined relationship with topographic features in their locality. This relationship is known as a 'boundary mereing' and is recorded within OS MasterMap as a textual description. A list of the most common abbreviations is given in the following table:

Common abbreviations for boundary mereings in OS MasterMap Topography Layer.

Object or mereing	Abbreviation
Baulk, bank, base of, basin, bridge, broad	B
Cam, canal, causeway, centre of, channel, cliff, conduit, cop, course of, covered, culvert, cut	C
Dam, ditch, dock, double, down, drain	D
Double ditch or drain	DD
Double fence	DF
Defaced	Def
Edge of, eyot	E
Face of, fence, fleet, freeboard	F
Feet	ft
Harbour, hedge	H
Inches	Ins
Kerb	K
Lade, lake, lead, loch, lockspit, lynchet	L
Marsh, mere, moat	M
Mean high water	MHW
Mean high water springs (Scotland only)	MHWS
Mean low water	MLW
Mean low water springs (Scotland only)	MLWS
Metres	M
Old	O
Passage, path, pond, post	P
Race, railway, ride, river, road, root of	R
Root of hedge	RH
Scar, sewer, side of, slope, sluice, stone, stream	S
Top of	T
Track	Tk
Undefined	Und
Wall, weir	W

The following table contains examples of combined abbreviations:

Combined abbreviations for boundary mereings in OS MasterMap Topography Layer.

Object or mereing	Abbreviation
Centre of bank, basin, baulk, broad and so on	CB
Centre of railway, river, road and so on	CR
Centre of old course of stream	COCS
1.22metres root of hedge	1.22 m RH

Special rules apply to boundary mereings, and only the more common ones are listed.

Where the mereing relationship of any boundary alignment changes or where a boundary changes from one side of a real-world object to another, the point of change is shown by a boundary half-mereing change symbol, usually in opposing pairs. The location of the boundary half-mereing symbol is coincident with the boundary alignment and not the feature to which it is mered.