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The Design and Implementation of National Economic and Social Statistical Electronic Atlas
3.2 GIS Software Platform Selection NESSEA is developed by Supermap Objects, which is a powerful COM-based GIS software platform. As ActiveX controls, SuperMap Objects control can be embedded into various visualized program language environments to implement system integration and development frameworks. 3.3 Database NESSEA includes four databases: meta-database, statistical database, custom database, and another is spatial database. Because NESSEA is a CD-ROM software system for public, Microsoft Access Database is chosen for meta-database, statistical database and custom database, and Supermap SDB Spatial Database is chosen for spatial database. 4 Main Functions In order to provide easy-to-use tools to query, display, visualize, and analyze statistical data for public, the system is designed to 5 modules. All the modules of NESSEA are described below. 4.1 Map Tools The module of “Map Tools” includes following functions: map selection, map browse, identify, measure, layer control, position, and export map. “Map selection” provides several modes, such as select by point, rectangle, circle, region or line, to select interested regions on the map. “Map Browse” provides common operation of electronic map, such as zoom in/out, pan, entire view, refresh, previous view, forward view, and also provides some peculiar functions. For example, “show higher level” or “show lower level” can show the map layer of higher or lower administrative division level by shifting map layers’ visible scale automatically and dynamically. “Identify” allows the user to identify an area, retrieve its attributes, such as name, administrative division code, and other indicators configed on “Basic Indicators Configuration Window”. “Position” allows the user to search units by coordinate, division code or name, and then position or select on the map. “Export Map” allows the user export the map to common image format file, such as BMP, JPEG file. 4.2 Indicators Query The module of “Indicators Query” includes two functions: Basic Indicators Configuration, and statistical indicators query. “Basic Indicators Configuration” can config the default indicators for query. “Statistical indicators query” allows the user to select indicators by tree or search indicators, set query condition, save query, and display the query results on “Table Window”. Indicators Query and the presentation of query results are based on Indicators-Space-Time (IST) Model. In IST Model, “I” is a collection or set of indicators; “S” is a collection of spatial units; and “Time” is a collection of time series of indicators. As shown in Fig. 2, IST Model is parsed and converted to 2-dimension tables by Central Controller Component.  Fig.2 Indicators-Space-Time (IST) Model |