A Research And Practice Of The Map Symbolization Control Technique In Digital Mapping

The technique of map symbolization control can greatly increase the effects and efficiency of map symbolization, and thus improve the productivity of digital mapping system. After analyzing and studying the map symbolization control based on program and control files, the author realizes the map symbolization control based on relational database. Taking advantage of relational databases' superiority in data management, the author designs and creates the symbolization control tables as the foundation of the map symbolization control technique. Furthermore, the author originally proposes and realizes the key techniques such as map template, geographic attributes expression, the control code of annotation position and the expression of annotation format strings. And then the author designs and constructs the user interface of map symbolization control, forming the complete system of map symbolization control and realizing the digital map symbolization control. Finally, the author puts the map symbolization control techniques in practice and achieves the expecting results. In this thesis the main research work includes the following aspects:1. The author summarizes the relevant theories, key techniques and problems of digital mapping; analyzes the role of map symbolization in digital mapping system, and the primary problems and difficulties of map symbolization; analyzes and discusses the current means of realizing symbolization control and their features.2. The author analyzes and discusses in detail how to realize map symbolization control in relational databases, for example, the design of various symbolization control tables, the role of symbolization control tables in the process of symbolization control, the logical relations between symbolization control tables and the logical flow line of realizing symbolization control in relational databases.3. The author designs and constructs the user interfaces of symbolization control, forming the complete system of symbolization control. What's more, the author suggests and realizes some key techniques: map template, geographic attributes expression, the control code of annotation position and the expression of annotation format strings.4. The author verifies this symbolization control technique in MapMaker archetypal system, illustrates the results with examples and finally makes an evaluation.