Foundation and Application of Electronic Map Multi-scale Display Models of Different Density Areas

According to the application demands, we divide geographical areas into four kinds. They are densest area, dense area, moderate dense area and sparse area. Aiming at different areas, the multi-scale display models are built to adapt their characters. Then, automatic estimation methods of different density areas based on RGB value are studied. On the basis of qualitative analysis and survey statistic, a hierarchical basic geographical elements display system is built. At last, taking examples of electronic maps of the area of mid-China, multi-scale display experiments are carried out.