A Method for Representing Thematic Data in Three-dimensional GIS

The effective representation of thematic data in 3D GIS can not only visualize tabular data intuitively in 3D environment, but also enable users to analyze thematic data directly on 3D GIS platform, thereby facilitating the decision making process. This paper proposes a method for representing thematic data in 3D GIS. Three steps are included in the method. In the first step, user is required to input some thematic representation parameters, all of which are then automatically converted into a XML fragment. In the second step, the API of the 3D GIS platform is employed to build graphic symbols according to the representation parameters and the thematic data. In the last step, we create legend and annotations to accurately interpret the meanings of the graphic symbols to user. This method has also been implemented as a module in a 3D GIS project named Digital Chongming Island, and the census data of Chongming Island are effectively represented in 3D environment.