正常高，大地高，非格网数据，地形影响。

GPS, normal height, geodetic height, non-grid data, terrain effect.

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本文介绍了一种简单实用的基于规则格网数据绘制高质量等值线图形的方法。

This paper introduces a simple but practical method to create high-quality contour line for grid data.

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在人口密度模拟的基础上，用GIS对上海人口格网数据进行简要的空间分析。

Then the temporal and spatial characteristics of population density change were analyzed based on GIS.

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