MONITORING THE LONG TERM URBAN EXPANSION OF ZANJAN CITY USING REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEMS

The growing phenomenon of urbanization, especially in developing countries, has led to the enlargement of urban areas. Due to the complex structure of cities, changes in the boundaries of a city, whether horizontally or vertically, affects the ecosystem and the quality of life of the corresponding communities. It is also important for the urban planners from the perspective of sustainable development to identify land use/cover changes. The purpose of this paper is to study and evaluate the spatiotemporal expansion of Zanjan city in five time periods. In this research, aerial photographs of 1973, 1982, 1998 as well as satellite images of 2008 and 2016 of the Zanjan city were used. After data preparation in GIS environment, each produced map was classified into two classes of built and not built. Two spatial distribution indexes (PD and CONTAG) as well as land surface and class level measurements were used to determine the characteristics of urban physical development in Zanjan. The results revealed that during the assessed time period, the city has become more sprawled, discontinuous, and in terms of variety of land uses has become more diversified. These results warn that if the urban expansion continues with the existing trend, historical contiguity and compactness of Zanjan city will loss in the near future. This trend may cause several problems