Using latitude and longitude is easiest along the equator, where the grid lines formed are roughly square.
沿着赤道使用维度和经度相当简单，形成的网格线大致也是方形的。
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DEM (Digital elevation Model) is a data set of plane coordinate or longitude, latitude, and elevation of the regular square grid points in some region.
This paper mainly introduces how to realize plottings of longitude and latitudegrid line, standard map fram and type of graph in the geophysical and geochemical map by WIN-SURFER system.