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Poster Session
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Geo-union: A coherent Geo Information System with environment analysis and planning
- The spatial data management module (SDMM)
This module is responsible for managing and processing data in vector form. It was five submodules:
- Map Directory. Every map is registered in the system map-directory, including its name, geographical subject, map-size, and other features of the map. The submodule also contains tables of attribute codes, each of which is considered to be a possible attribute value attached to a spatial entity such as a polygon, a line or a point.
- Map Inputing. Interactively map inputing through digitizer or converting maps from remote sensing data (in raster form) into vector structures.
- Map Editing . Various functions are provided for modifying the detail of geometrical positions and spatial relations between spatial entities within a map, In addition, and attribute code can be entered by keyboard and attached to each spatial entity.
- Map Operating. Operations on maps such as map overlapping, map clipping, map joining, polygon selection, and polygon merging are available to create new maps by operating on existing maps.
- Map drawing. User can interactively indicate many features with a drawing such as definition of a map legend by using a library of legend symbols (Fig.2) the drawing size, map name, the relative position of map areas for showing the map name and the legend. Functions for annotation in both English and Chinese are also provided.
- Main characteristics of the system
In addition to the basic functions which every GIS system owns, GEO-UNION system can be characterized by several main features.
- Procedures for map formation
There are five ways of extracting data to form new maps in vector structure:
(a) Converting data from image processing (b) Processing data from plan comp equipments (c)
Extracting data by using DTM module [2] (d) Ordinary digitization . (e) Extracting data by data analysis. For example, soil erosion maps can be formed by an application module of soil evaluation.
- Coherent handling of maps represented in two kinds of data structures (in vector form or in raster form) . GEO-UNION system maintains each map in one of the two representation forms according to its data source and its usage. (Fig.3) In order to facilitate the conversion of a map from one representation into another parameters such as the number of grids(rows and columns) in one map can interactively be defined.
- Working with Relational data base system ORACLE We have developed an interactive query system Geo-Query based on the connection between the spatial information mangement and RDBMS (ORACLE)[3]
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