SEVERAL KEY ISSUES IN GIS DATABASE DEVELOPMENT
Shao Quanqin (Department of Geography, Capital Normal University, Beijing 100037)
Database is a base-stane of a GIS system. The establishment of a database takes not only quite lots of money but quite lots of labor and time resource as well. In China, numerous GIS systems have been established for differant purpose. Although the database technology has been mature, there are many problems which should be taken into consideretion in establishing a database, or the database established by quite high investment would be a ″garbage″. This paper was to discuss several important issues in developing a GIS database, based on our experience and practices of lots of case studes:(1) Normalizing attributes table and designing relations between tables. Using a example of land register database in Fangshan District, BeiJing. His paper had discussed:① relations between attributes tables defined by system and by user; ②relations between attributes tables defined by user;③ according to functional depondency, descompose a unnormalization table to normalization tables (3NF) having stacking relations.(2) The design of exampling elevation data.Using, example of elevation data base in Huaihe river basin (from Huaibin to Benbu). this paper had discussed: ① selection and unification of elevation datum plane;②selection of exampling method; ③ design of exampling distance; ④ particular dealing with dyke and river elevments in flood elevation database.(3) The registration of spacial information. Using example of Huaihe river basin and evaluations about flood disaster situations of Fuji and Gangdon in 1994. This paper had discussed:① the registration of spacial information from different scale maps: ② the registration of spacial information from maps and image ;③ the registration of image data from different remote plat form and from different time phese.(4) The data quality control of GIS database: ① the precision of source data and controling and checking method;② the precision controling of derivative data;③the temporal truth of data and solving method;④using data dictionary to trace the data quality.