A sheet of salt water separated from the open sea by sand, shingle banks or a road embankment. The sheet of water between an offshore reef, esp. of coral, and mainland. The sheet of water within a ring or horseshoe shaped atoll.
Data Dictionary for lagoon_poly: http://apps.linz.govt.nz/topo-data-dictionary/index.aspx?page=class-lagoon_poly
This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.
Further information on Topo250: http://www.linz.govt.nz/topography/topo-maps/topo250
LINZ and our predecessors have been responsible for national topographic mapping in New Zealand for more than a hundred years.
The first digital data at 1:250,000 scale was created in the late 80's by scanning the 1:250,000 maps that existed at the time (known as the NZMS 262 series, which replaced the earlier NZMS 18 series)
The NZMS 262 series were generalised from the NZMS 260 series.
The Topo250 map series are compiled from a mix of information from the NZMS 262 series, and that from the Topo50.
LINZ releases regular updates of the Topo250 maps and data. Details are posted at http://www.linz.govt.nz/docs/topography/250-sheet-history.xls