Haleh Hoseinpour - Professor, Urban planning Department, University of Tehran, Tehran, Iran.
Esfandiar Zebardast - Department of Art & Architecture
Hamid Majedi - Professor, Urban planning Department, Faculty of Art and Architecture,Science and Research Branch,Islamic Azad University, Tehran, Iran.

The expansion and growth of cities is a remarkable phenomenon in urban planning literature,so that unpredictable developments have become more evident in recent decades, especially in cities that haveundergone changes in their physical structure following the promotion of their political role. The present paper seeksto identify the factors driving growth in the developed areas of Ardebil city and extract basic factors and variablesby investigating development of Ardebil. In this study, 27 variables have been tested in 920 expansion blocks duringthe years 1996 to 2011 using GIS and factor analysis. Four main groups including congestion factor, external factor,access factor and facilities are identified as driving forces of growth. The final combination of four factors in the ArcGIS environment show that the north, east and south east blocks of Ardebil had a higher score than the other blocks;in other words, these factors have the most effect on the growth of these areas. In addition, the Southwest blocks withthe lowest score of between 0 and 2 have had the least impact from among the factors mentioned.

Urban expansion, Growth factors, Factor load, Factor analysis