The auto-adjustment of electronic map color based on the provincial area mode of China

Area properties of mapping region has important impact on expressive effects of color grading symbol, which is mainly reflected in two aspects: firstly, color´s area proportion in mapping region will affect the strength of visual impact from color, which can influence maps´ clarity and comfort; secondly, area difference between different classes will affects visual perception caused by original color grading symbols, which can cause visual illusion. Based on China´s provincial area model, this paper explores how to recognize the problems caused by area difference, and provide thought of auto-adjustment of traditional color grading symbol. Then the paper realizes the method using Visual C# and Supermap Object to realize a system having the function of the auto - adjustment of the map color.