一座城市平面图：城市面积约6000平方公里，形状接

A city plan: the city covers an area of about 6000 square kilometers, with a shape close to a diamond, facing the sea in the southeast and northeast, and inland in the southwest and northwest. There is a north-south main river running through the whole city. The main river has eight east-west tributaries. The main urban area is to the west of the city center, covering an area of about 600sq km. There are four deputy urban areas with an area of about 150square kilometers in the eastern part of the main river, and six resorts with an area of about 50 square kilometers in the eastern part of the main river. The main urban area is divided into commercial and residential areas, covering an area of 4:6. There are schools and hospitals in residential areas, and vice-urban areas are divided into commercial areas and residential areas, covering an area of 2:8, and residential areas have schools and hospitals. The resort area is divided into recreation area, hotel area and villa area, covering an area of 5:3:2. There is a logistics area of about 50 square kilometers in the upper and lower reaches of the main river, and a wind power generation area of about 30 square kilometers on the east coast. There are 20 small urban areas with an area of about 50 square kilometers randomly distributed in all parts of the city. The small urban areas are divided into commercial areas and residential areas, and the proportion of the area is 1:9. There are schools and hospitals in the residential area. The main urban area, vice-urban area and villa area are connected by highway.