Thus the name 'Singapore Strait' in a document may not refer to the channel of that name on a current
hydrographic chart, but to any one of four possible arteries: the Old, New, Governor's (or John de Silva's) and Johor Straits.
Pakistan Navy Hydrographic Department (PNHD) is playing its prime role in fulfilling the international obligation of undertaking Hydrographic Surveys and production of
Hydrographic charts in a befitting manner.
The Library's Map Section is using this funding to complete cataloguing and scanning of the following four groups of material: Pacific and SE Asian maps (Pacific countries and East Timor completed, Brunei, Indonesia and PNG progressing) ; Australian state and territory maps (starting with Tasmania and NT) ;
hydrographic charts (spreadsheets listing over 40,000 charts from two dozen navies are now searchable in Trove, digitisation to commence shortly); and various 'formed collections' such as the Australian Inland Mission map collection.
But future expeditions failed to find the island, and it was removed from some official
hydrographic charts by the 1970s.
There are over 1,500 unknown wrecks and underwater obstructions listed in the
hydrographic charts of the British Isles.
It's a specific take-along or trip-planning guide for sailors intended to compliment official
hydrographic charts and offers hand-drawn shoreline plans of marinas, small boat anchorages, marine parks and more.