The analysis of sprawl sirjan city and future growth'by remote sensing data

Document Type : Articles extracted from Thesis


1 Associate Professor of Geography and Urban Planning, Shahid Bahonar University of Kerman, Kerman, Iran

2 associate professor of shahid bahonar university

3 geoghraphy and urban planning



Analysis of Urban Sprawl of Sirjan and future growth using Remote Sensing Data

Extended Abstract
Like a living creature, a city develops because of various factors such as population growth and the expanding scope of human activities. As a result, the city's physical range also increases in different vertical and horizontal directions. Cities can't accommodate the increased population; thus, a part of the population is driven around the city searching for better living spaces. In this case, rural districts near the city are the most likely to attract this kind of population. It then becomes a question of what must be done. That is, what is the solution? Studying urban development and determining its causes and factors may be helpful. In the province of Kerman, there is an important and more significant city named Sirjan, which is characterized by relatively flat terrain, and the slope is from northeast to southwest, and therefore general directions for building the body and textures of the city are northwest-southeast and northwest-southwest. A fragmented development has come about due to the city combining several villages nearby as it expanded and developed. This research seeks to answer the following question: how has Sirjan become more urbanized over the last few decades? What will Sirjan's future look like in the next 30 years? This study aims to examine Sirjan's urban sprawl during 20 years from 1990 to 2020. The sprawl directions and rates will also be examined to understand the city's urban growth balance better.

The types of applied research and the methods used to conduct it are descriptive-inferential and analytical-combined. According to the proposed hypotheses, the current study aims to assess historical physical development and forecast future physical growth till 2050, and how the surrounding villages of Sirjan city will change. The method has been deductive and inductive in using theoretical foundations, models, and methods, and generalizing results and suggestions, respectively. Because of the interaction of human and economic issues, the research took a systemic-structural approach. The Landsat satellite photos from the period (1985-2020), with a 5-year interval, were initially employed in this study to meet the research aims and to answer the research questions. The photos were then corrected for atmospheric and radiometric effects, and the results were derived using a supervised classification approach of changes in Sirjan over the statistical period under consideration. The results were validated using the Kappa coefficient. The satellite photos used in the study came from the Landsat 5, 7, and 8 satellites, as well as the TM, ETM, and OLI sensors. Also, in this study, the entropy model has been used to determine the urban misery and sprawl of Sirjan.

Result and Discussions
The photographs associated with each statistical period have also been processed. In this part of the report, the number of land uses (constructs) has been described by geographical directions separately. To determine the area of structures in each geographic direction, first satellite images in SAGA software are cut according to the study area and then processed based on samples taken from Google Earth. ENVI is used to classify the output of this software. Then, the output from the GIS program is called, and the area of Sirjan's constructions is determined in terms of each geographical direction. The Markov chain model was used to assess changes in building in the study region during the next 30 years leading up to 2050, as well as to demonstrate which settlements in Sirjan will be integrated with the city's progress. The Markov chain model utilizes cover classes as state or chain states. According to projections, the city of Sirjan will have a total area of 90.84 square kilometers in 2050, thanks to the expansion and integration of Najaf. The above is also supported by the statistical period's entropy results in terms of eight geographical directions. According to the findings, the entropy value for the eight directions of Sirjan city buildings is 2.0258, which is lower than the standard and final value of 8, which is 2.0794, indicating the accuracy of the technique results. Secondly, the calculation value, equivalent to 2.0258 and is extremely close to the standard and final levels indicates that urban sprawl in Sirjan has been confirmed in terms of geography and intensity.

The study of the progress of Sirjan city during the statistical period of 2020-1990 showed that the most construction was done in the east at the beginning of the period. However, toward the end of the period, the northwest had the most significant number of constructions. In the northwest direction, the percentage was more than in other directions. It is estimated that the area of this geographical direction at the beginning of the period was 0.875 square kilometers, while at the end of the period, it was 6.513 square kilometers. Since the beginning of the period, the area of the city in the south has increased 4.64 times. At the beginning of the period, the area of the city in the southern part was 0.864 square kilometers, and by the end of the period, it was 4.868 square kilometers. The city's expansion is more in the west than in the east, and the area of construction in this geographical direction rose 3.51 times by the end of the period compared to the beginning. According to the findings, the construction of Sirjan city or, to put it another way, the crawl of Sirjan city in 2000 caused Firoozabad village to be merged into urban structures, and this is expected in the following years due to Sirjan city's rapid expansion and crawl. Sirjan's urban construction will also include the villages of Jafarabad, Basferjan, Mohammadabad, and Ferdows Abad.

Keywords: Physical Development, Urban Sprawl, Remote Sensing, Sirjan