摘要：Geography has been making more frequent of the concept of density of population It is a simple concept of relating population size to the land area with a view of assessing crudely the pressure of population upon the resource of the area. Thus it is a measure of the incidence of population concentration and is generally expressed in terms of per square unit (km./mile) of land area rather than of gross area (land and water). The numerator in this calculation is population (p) and the denominator is area (a). Thus Pd = P/A
