The Design And Implementation Of Dot-Form Symbol Library For GIS

This paper comes from a design of dot-form symbol library for Geograghical Information System (GIS).Map is an essential part of GIS. GIS delivers information to its users by maps. To a map, symbol is its language. The symbol library is a database used to manage those map symbols. In a symbol library, dot-form symbols play an important role. A high displaying quality and efficient dot-form symbol library is crucial to a good GIS.The dot-form symbol library we formerly used uses vector format. As a very popular symbol format, it has a lot of merits. But, it also has two main demerits: weak describing ability and low displaying quality.This paper introduces how to use a new dot-form symbol describing technology to solve those two problems. This technology comes from the famous font describing technology, TrueType. After analyzing the TrueType describing technology, we have a new dot-form symbol describing technology, Contour Line Dot-Form Symbol Format. This new format has higher describing ability and displaying quality compared with vector format, it well solved our problems.This paper also introduces the design of file format and management software for dot-form symbol library. When designing the file format, being efficient and easy to use are the goals. When designing the management software, I want it to have all the frequently used functionalities, to be easy to use, and very importantly, to be expansible. This paper also introduces some design patterns used to design the management software.Finally, this paper introduces how to apply the new dot-form symbol library to existing GIS, it also has an evaluation for the application. This evaluation may be useful to designers of GIS or symbol library.