تأثیر مبادلات اقتصادی در توسعۀ شهرهای مرزی (مطالعۀ موردی: شهر پیرانشهر)

Introduction
Urban growth and development in all countries, to a certain extent, is a function of geographical location. Central cities usually exhibit faster growth when compared to peripheral cities. A border city is a spatial residential phenomenon located within a certain distance of the border. The growth of such a city follows factors such as economic, cultural, and political exchange with the interior and exterior space of the country. These factors can guide the city towards the development of certain actions, and thus play an effective role in its spatial development. Studies of the development of border cities, same as all other cities in Iran, show that their spatial growth and development can be traced back to economic changes such as cross-border exchange and higher emigration to cities. The development of a border economy in recent years, whether legal (the border arcade of Tamarchin) or illegal (smuggling), has paved the way for higher economic growth in Piranshahr. It is clear that the development of economic activities has created more employment in the city, therefore attracting a higher population (immigration friendliness) and leading to urban growth. The population in 2011 (about 70 thousand) compared to the population in 1966 (about 4848) clearly indicates this.
Methodology
The research methodology used in this study is descriptive-analytical. The required data was collected through library research, official organizations, statistics, and fiend studies. In order to prepare data for analysis, the raw data was imported to Excel 2013, where all required tables and figures were extracted. The Bujogarnia Diagram was used investigate the economic role of the city, which was measured by analyzing the number of active population in all three major occupational groups: services, agriculture, and industry. In addition, the rate of growth was calculated for the phenomenon of land-use change, the map of which was created in GIS.
Discussion
Due to the development of cross-border trade and higher population growth, the city of Piranshahr has undergone numerous changes and transformations, as is evident from the widespread land-use change, which is a major indicator of physical growth and change in cities. From the obtained information, it can be inferred that economic exchange has had a serious impact on the growth and decline of certain land uses. Commercial use of land has grown by 10.22 percent. Urban green belts have enjoyed a significant growth rate of 14.94 percent in uptown in order to accommodate for the passengers, decorate the city, and create a healthy space for free time activities. Also, residential and transit network use have increased by 6.95 and 5.51 percent, respectively. On the other hand, due to higher security, population persistence, and higher convergence of the people with the center, which have resulted from economic growth, military land use has faced a negative growth rate of -4.95 percent. In sum, the land area of Piranshahr city has expanded from 446.4 hectares in 1995 to 844.45 hectares in 2011, i.e. it has nearly doubled. Therefore, the process of changing Piranshahr from a military-security region to a service-commerce region can be an important factor in the steady spatial growth of the city. The results of the Bujogarnia Diagram confirm this claim. According to this diagram, the city has tended towards a multi-role paradigm (service-commerce). Initially, according to the 1996 consensus, the city had a service-dominant role; this can be ascribed to the high population of military sector, which was considered a part of the service sector. However, in the following consensuses, the city shifted towards a service-commerce city. This manifests itself in the decline in the number of military employees and the increase in the workers of other service-related areas and subordinate jobs, which was a result of more commercial/cross-border activities. Another important conclusion that can be drawn from this study is that economic exchange has increased employment and attracted commercial tourists to the city. According to statistics obtained from the Cultural Heritage and Tourism Organization of Piranshahr, during the first 20 days of the year (i.e. Nowruz vacation), 2,509,667 people have visited the city from 2010 to 2014 in order to purchase inexpensive imported goods, i.e. 501,933 people on average have visited the city during the first 20 days of each year. In sum, this study reveals that the city of Piranshahr has experienced significant physical-spatial and economic development, highly as a result of granting formal status to the border arcades of Tamarchin and the increased amount of cross-border exchange through informal means; this calls for the immediate attention of the authorities to provide the required infrastructure and allow for more serious growth and dynamism of the city.
Conclusion
Results of the analyses performed on the development of Piranshahr city confirm that economic exchange with Iraqi Kurdistan has had a positive impact on the development of the city. The results indicate that the economic growth policy of the Iranian government in recent years, followed by the expansion of cross-border trade and commerce, has had a significant positive impact on the physical development of Piranshahr. Cross-border trade has local and even regional-national effects on the economy; and the development of economic centers (border arcades) as a result of economic exchange, has led to physical development and change in the city.