The type of spatial data model: the model based on object (element); network model; field model.

空间数据模型的类型：基于对象(要素)的模型；网络模型；场模型。

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By VRML, the users of the World Information Network can view spatial model, without being confined to planar graph, image.

通过VRML，全球信息网的使用者可以观赏到立体空间的模型，而不限于二维空间的图形、影像。

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By means of GIS method, the digital elevation model(DEM)is established, the flow direction, flow accumulation, subcatchment boundaries and stream network spatial distribution are studied.

采用GIS的方法，建立了环县数字高程模型（DEM），研究了本区地表水流方向、集流能力、子集水区的划分及水系网络空间分布等水文特征。

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