Can someone give me a detailed definition of a Sphere of influence please?

Question

Can someone give me a detailed definition of a Sphere of influence please?

Answer 1

The area surrounding a settlement or service (for example a leisure complex) that is affected by the activities of that settlement or service. The sphere of influence may be mapped by looking at the catchment areas of various services or by considering local-newspaper circulation, delivery areas, and public-transport destinations.

All settlements are central places with functions such as housing, administration, health care, shopping, and recreation. The number and hierarchy of these functions determine the area of the sphere of influence and depend on the size and importance of the settlement – whether it is a village, town, or city.