On the Study of Vertical Datum for Hydrography and Cartography

In this paper,the classification of vertical datum for hydrography and cartography and their function for the expression of spatial ocean information are analyzed.The mode of vertical datum for modern hydrography and cartography is demonstrated.The concept of seamless chart datum and its realization is illustrated.The multi-grade structure of hydrography vertical datum is designed.The transformation between the different kinds of vertical datum is researched and the quality control and the applications of the hydography vertical datum system are discussed.This research aimed at the construction of a modern vertical datum system for hydrography and cartography.