ABSTRACT
Hydrographic surveying has for centuries provided the primary data for nautical charts and publications. The requirement for these vital documents originated from our ancestors' need to navigate trading vessels safely along the world's steadily extending network of sea routes. The advent of the use of the compass at sea in the twelfth century gave rise to longer voyages out of sight of land, thereby driving the need for the specialist nautical chart. In the colonial period the various imperial powers undertook surveying and charting of their dominions as part of supporting their maritime trade interests, trade routes and command of the sea. The International Hydrographic Organization is recognised by the UN as its competent authority in the fields of hydrography and nautical charting. National, international and global hydrographic programmes are coordinated through a series of regional groupings and through the organisational structure of the International Hydrographic Organization.
