系统提供了地图操作功能，例如放大、缩小、导航图、图层管理。

The system offers map operation function, for example: zoom in, zoom out, navigation map.

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在地图管理结合图层管理和块管理，更加方便用户使用和节省存储空间。

Block management is combined with layer management in map management function in order to make user use the software more conveniently and save the storage space.

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最后简单说明了数据结构转换、坐标系转换、图形裁剪与分幅、图层管理以及应用计算等功能。

At last, this paper narrates several issues, they are conversion of data structure, conversion of coordinate system, cutting out and disparting of map, the management of layer and applied calculation.

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