# Delineation Of Functional Regions

Delineation Of Functional Regions

• This method involves the grouping together of units which display a considerable degree of interdependence.
• Two basic approaches: (i) Flow analysis- based on actual observations of what people do.   (ii) Gravitational analysis- based on theoretical observations of what they might do.
• The two approaches are explained below in detail.

A. Flow Analysis Method

• Builds up flows on the basis of the direction and intensity flows between the dominant center and surrounding satellites.
• Flows may be of several types: economic (road, rail, shopping or commuting); social (such as flow of students or patients); political (flow of govt. expenditure); information (newspapers, telephone calls), etc.
• Graph theory: measures the relationship (economic, social, etc) between selected group of centers on the basis of flows between the centers. The no. of telephone calls is the usual flow criteria.
• The flows are plotted in matrix form, from which primary and secondary flows into and out of each center can be identified.

B. Gravitational Analysis Method

• It is concerned with the theoretical forces of attraction between centers rather than the actual flows.
• This model assumes that the interaction between two centers is directly proportional to the ‘mass’ of centers and inversely proportional to the ‘distance’ between them.
• ‘Mass’ is represented by variables like population, employment, income, expenditure and retail turnover.
• ‘Distance’ is represented in physical terms (miles), time, price and intervening opportunities.
• Mathematically
• By calculating the potential for the centers, lines illustrating relative attractiveness, spheres of influence of various centers can be plotted on a map.
• From such lines, functional regions can be identified.