A DIGITAL CARTOGRAPHIC SYSTEM BASED ON FUNDAMENTAL GEOGRAPHIC INFORMATION
H. Zhu, H. Wang, L. Li
Wuhan university,School of Resource and Environment Science,Wuhan,China
The main purpose of digital cartographic system based on fundamental geographic information is to fully explore the knowledge process of cartography based on topographies of basic national scales, and solve various kinds of problems in the mapping process. The digital cartographic system, which is in the constraint of cartographic rules and in according to basic national topographic maps, provides infrastructural geographic information data with scientific basis and tools of transformation from spatial data to cartographic data, realizes the conversion from data to maps, and successfully solves the problem in this process.
This system mainly includes these parts: symbolization of maps, the handling of the relationship of features, automatic deployment of annotations, decoration outside the map-outline and output of data.
The symbolization of maps mentioned here does not simply handle features according to the symbols given, but to deal with complicated relationships of various kinds of features based on symbolization, mainly including the setting of displaying orders of layers and features, automatic mapping of transport network, gradual-changing handling of rivers.
Relations of features are classified into two parts: attachment relationship and collision relationship. Attachment relationship is an interdependent relationship between some point features (such as railway stations) and line features surrounding these point features. The collision relationship is various, which mainly includes detection and handling of features in many situations such as point-point, point-line, point-area etc.
The automatic deployments of annotations mainly include the automatic deployments and the detection and the automatic movement of annotation overlays after deployments. The difficulty lies in the determination of handling methods for relationships between several objects with the same name and the same name with several annotations, and also between annotations and features.
According to the map schema in each scale, the location of each decorative feature can be calculated in terms of TIC. When designing the system, the content of outer map-outline can be input by users or acquired from metadata files automatically. Currently, the main form of the output of the system’s data is in the interactive format of EMF.
In order to test the stability and feasibility of the system, it has been on trial in the production department already. The result of experiments manifested that the mapping speed has been greatly accelerated after using our system. In light of different scales, the digital mapping of a topological map can be finished in an half to two days by our system.