Opening Design of the Symbols on Topographic Map

In this paper, the design and establishment of point, line and area symbol on topographic map have been discussed by use of object-oriented technique and template method. The main idea of template method is that the smallest cyclic entity of point symbol, line symbol and the smallest unit of area symbol are put across template, and then template can be combined or transformed according to the spatial data to be symbolized to create point symbol, line symbol and area symbol. Point symbol and area symbol can be acted as an especial line symbol according to the features of point symbol, line symbol and area sybmbol on geometrical distribution and the idea of template method. Symbol template can be put into the symbol base after it has been designed. The symbol can be edited and maintained in the symbol base. The designing way, establishment of symbol base and its key technique are also analyzed. Also the opening visual designing environment of map symbol has been introduced. The design of symbol is a stitch in time saves nine with a convenient and agile design means which provides many edit tools and methods, realize the visual design of symbol, accomplish the symbol design quickly and expediently. Visual designing environment improves the size and position precision of symbol by the view management and active ruler.