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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This paper mainly introduces how to realize plottings of longitude and latitude grid line, standard map fram and type of graph in the geophysical and geochemical map by WIN-SURFER system.
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.