Study on Land Use Management with
Geographic Information Systems
3. Database
3.1 Database Organization
The database has three sub-databases such as geographic and land use database, project database and test database. Herein, a tree structure was designed to manage these data. The graphic and geographic database including the land use data is the primary database for the system. This database consists of sixteen coverage items such as land use, geology, soil, water system, road system, boundary line, forest map, and national park map, coastal conservation map, slope map, relic place map, natural ecological protection map, water quality and water quantity conservation map. The project database stores the data generated from each individual project. The test database is a temp directory for the data generated from the system test. The following paragraphs describe data processing and the contents of the geographic and land use database.
3.2 Data Source and Gathering
Three types of data were used in the database: the coverage obtained from Construction and Planning Administration, digital topographic maps published by Interior of Ministry, and 40m by 40m Digital Elevation Model (DEM) supplied by Center for Space and Remote Sensing Research, National Central University.
The processes, transferring the source data to database, include generalization, aggregation, and reclassification. The generalization of coverage is to eliminate the unwanted attributes and graphic entities in the coverage. The aggregation of features in the coverage was to combine the data with the similar characteristics to the same category. The reclassification of features in the coverage set the new category for the selected data according to the specified conditions. While the data are input to the database after the above processes, the description data that are relevant to the data should be established sequentially.
3.3 Metadata
The metadata offered by the database greatly benefits the understanding of the data users. In addition to the database description, the metadata can support the functions of analysis tools, for example, attribute selection (Ho, 1997). The metadata not only enhance the understanding of the users, but also assist the item selected in the analysis system. Figure 2 presents an example of usr interface created from metadata. The elements of metadata include database description file, project description file, attribute list file, code table list, code table, map boundary file, project list file, coverage list file, coverage description file, the results list file, description file of the results and map symbol description file. .The detail description of metadata can be found in Ho (1998).
Figure 2 An example of user interface creating from metadata
4. Case Study
4.1 Study Area
The study area for potential areas of slope disease is the Nantou County, a mountainous district in the central Taiwan. Owing to the weakened geologic formation at some areas in the county, the natural disease occurs annually. Notably, the pollution and environmental damage are slight because the primary land use is agriculture and forestry.
4.2 Rules of Delineation
Figure 3 displays the procedures and the rules to delineate the potential areas of slope disease. The rules derived from the construction laws, The White Book of Construction Planing Strategy, and reports of Construction and Planning Administration (1993) and Chen (1993). The construction laws referred Yiin(1997).
Figure 3 The procedures and rules for the case study
4.3 Results
Figure 4 represents the potential areas of slope disease in this case study. Some disease areas of 921 earthquake in 1999 just located nearby the predict areas in Figure 4. Although the rules conducted in this case study were not novel, the system had the capability to find out the similar areas on real disease areas. More rigorous investigation should achieve more exactly prediction.
Figure 4 The potential areas of slope disease
