Assessing the Spatial Difusion of Population in Small and Medium-Sized Cities from the Central Core Under Horizontal Growth Conditions (Case Study: Torqabeh City)

The present study, using spatial analysis models and in the framework of the "spatial diffusion" approach, has evaluated the position of the central core of Torqabeh city from the perspective of population groups. This evaluation includes two periods: 1- Slow growth (before 2006) and 2- Rapid growth (after 2006). Research variables include population, number of women, elderly, youth, employed, unemployed and illiterate. The scale of analysis comprises 1476 urban blocks and three periods of 1996, 2006 and 2016. For this purpose, a spatial database including the population characteristics of Torqabeh city and its central core was created and then data were analyzed using spatial statistical tools and techniques such as Getis-Ord Gi and Grouping Analysis. The results of this evaluation showed that before 2006, the central core was the origin of all population groups and was different from other urban areas. But after 2006, population groups with the dominant pattern of "continuous spatial diffusion" move out from the central core and settle around it. Spatial analysis models show that as a result of these changes, the central core of Torqabeh does not lose its position compared to other urban areas. Rather, this process causes some areas to become more similar to the central nucleus and the population characteristics of the central nucleus to be multiplied in other regions. The spread of population groups around the central nucleus and its adjacent areas, on the one hand, indicates the desire of individuals to be present in this area and show spatial cohesion, and on the other hand indicates the existence of a distinct pattern of central nucleus changes in physical growth which is different from common patterns in large cities.