What are the spatial forms of population migration?

● International population migration by geographical scope refers to the migration activities of people crossing national boundaries and changing their residence within a certain period (usually 1 year). International migration has occurred continuously in history, and the biggest one is the climax of migration from the old continent to the new continent since the geographical discovery of15th century. The main directions of modern international immigration are: ① Europe continues to immigrate to the New World; (2) African slaves were forced to sell to America; (3) China, Japanese and Indians began to migrate to Southeast Asia, America and Oceania. After the Second World War, the characteristics of international immigration have changed: the immigration to the new world that lasted for hundreds of years is coming to an end; More and more foreign workers flow from developing countries to developed countries; Due to the frequent outbreak of regional political conflicts, international refugees are constantly emerging. The characteristics of international population migration: before World War II, a large number of people migrated from the old continent to the new world; After World War II: Short-term Flows from Developing Countries to Developed Countries. ● There are differences in the direction of safe migration. Domestic migration is more frequent and common. The main forms include: ① Border reclamation and immigration. Due to the unbalanced economic development between regions, the population in resource-exhausted areas is relatively surplus, and population migration is accompanied by the development of new land. Since modern times, the development of the western United States, Siberia of the Soviet Union and northeast China has attracted a considerable number of immigrants and lasted for a period of time. Due to different national conditions, reclamation and relocation are sometimes carried out spontaneously, and sometimes planned or military reclamation is adopted; ② The rural population is concentrated in cities. This is a more common and important modern domestic migration. Its essence is the transformation from agricultural population to non-agricultural population, which is closely related to industrial agglomeration and the development of commodity economy. /kloc-after the industrial revolution in the 0/8th century, cities in western Europe and North America became the locations of big industries, and a large number of rural people poured into cities. After World War II, the wave of migration to cities swept the world. Developed countries are caused by the reduction of labor required for agricultural modernization, and the development level of rural and urban areas is getting closer and closer; The development of modern cities in developing countries is relatively late, with a large agricultural population and great differences between urban and rural areas, which leads to the increase of unemployment and the deterioration of urban environment. Characteristics of population migration in China: In ancient times, people moved from places with poor natural conditions to places with good natural conditions, and moved in large numbers; Modern: from the founding of the People's Republic of China to the mid-1980s: planned and organized migration from the east to the northwest and northeast; Post-80s: from the west to the east, from rural to urban, spontaneous migration, a large number.