Within two opposing grids, several major cities in China (such as Beijing, Shanghai, etc.) are marked, so that the location of these cities can be accurately drawn to draw the outline of China. Place the main land outline in the most central area of the nine-square grid. Please note that the ratio between the Northeast region and the Tibetan Plateau needs special attention, which is more complicated, and the original map needs to be compared multiple times to ensure accuracy when accurately describing.