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An object-based spatial database is a spatial database that stores the location as objects. The object-based spatial model treats the world as surface littered with recognizable objects (e.g. cities, rivers), which exist independent of their locations. Objects can be simple as polygons and lines, or be more complex to represent cities. While a field-based data model sees the world as a continuous surface over which features (e.g. elevation) vary, using an object-based spatial database, it is easier to store additional attributes with the objects, such as direction, speed, etc. Using these attributes can make it easier to answer queries like "find all tanks whose speed is 10 km and oriented to north". Or "find all enemy tanks in a certain region". Storing attributes with objects can provide better result presentation and improved manipulation capabilities in a more efficient way. In a field-based data model, this information is usually stored at different layers and it is harder to extract different information from various layers. This data model can be applied above the ER as in GERM model and GISER. S.Shekhar introduces direction as a spatial object and presents a solution to object-direction-based queries. ==Data model representation== The most common representations for the data model follow. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Object-based spatial database」の詳細全文を読む スポンサード リンク
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