Document Type : علمی - پژوهشی
Authors
1 Golestan University
2 Ferdowsi university of Mashhad
3 Ferdowsi University of Mashhad
Abstract
Extended Abstract
1.Introduction
The physical developments of cities are considered as the main factors of changes in the land use and the land cover. Urbanization has put the living conditions of urban residents at the risk of destruction by creating the most extensive manipulation of human in nature. However, urban development and changes in the land use patterns cause widespread social and environmental impacts.
These impacts include the reduction of natural spaces, the increase of the vehicles concentration, the reduction of the agricultural lands with high production potential, and some impacts on the natural drainage and water quality. These impacts are somehow related to the changes in the land use patterns as a result of human activities. Therefore, it seems vital to understand how changes in the land use and the land cover look in terms ofthe quantity of these changes and their special patternsbecause they have wide impacts on the environment, water cycles, natural habitats and so on.
So the understanding and modeling of these changes are considered as important issues for environment managers, planners, and municipalities. On the other hand, physical development of the cities is eliminating and destroying fertile agricultural lands.
2.Review of the Literature
One of these physical development effects includes development at the suburbs or countryside districtslocated beyond the administrative boundaries of the cities. This urban development has gone into the outer areas of the cities and can lead to changes in the land use over there. Furthermore, the physical urban development will eliminate and destroy high-quality agricultural lands.
At their initial stages of formation, most of the cities in Iran were established near or among the high-quality agricultural lands with the purpose of using high-quality soil for agriculture and then these lands were gradually buried under the cities through villages development.Accordingly,agricultural activities were inevitably receded to the poor lands.
The physical urban development is a dynamic and continuous process in which the city boundaries and its physical space increase in the vertical and horizontal directions both quantitatively and qualitatively. If this process is a rapid and unplanned process, the city space and body will be faced with some problems.
3.Method
Landsat (MSS) satellite images taken on 1976/01/06, Landsat (TM) satellite images taken on 2007/29/06, aerial photographs 1:20000 taken in 1979, and land use map 1:250000 prepared in 1998were used in this study.
In addition, ENVI 4.7, IDRISI Selva and ArcGIS 9.3 software were used for data processing, manifesting, modeling, and getting output.Maximum likelihood method was also used to classify the uses.Analogy after classification was then used to examine changes in uses. Finally, logistic regression model was used for the anticipation of changes.
According to the desired classes for classification (of urban and non-urban areas) before the collection of the urban information so as to prepare an actual map of the ground and a map from the training samples, first the colored pictorial data obtained from the satellite images were generally identified and the urban and non-urban areas were specified on them. Then,50 samples of each class were selected through GPS system by referring to the cities and a map was then prepared with a raster structure according to each of them. Finally, the maps resulted from classification were compared with the actual map of the ground.
4.Results and Discussion
The results of the images classification showed that about 168 hectares of the entire city were covered by the residential areas in 1976 and non-urban lands were about 6025 hectares. On the other hand, in 2007 the urban lands were about 1683 hectares and non-urban lands were about 4510 hectares. The results of the comparison of two classification maps related to the beginning and the end of the period showed that 1515 hectares hadbeen added to the urban area during this period due to the construction.
When the location and level of the residential areas development were determined, logistic regression was used to determine the relationship between the factors associated with this phenomenon. Digital data such as distance from roads, distance from treatment centers, distance from educational centers, distance from arid lands, distance from parks and gardens, and the domain slope and direction were prepared at GIS environment as independent variables of the regression model and then a logistic regression relationship was established between the urban development as the dependent variable and the mentioned parameters.
According to the results, Pseudo R2 amount was equal to 0.2808, so the model fitting can be considered tolerable. On the other hand, the ROC amount was equal to 0.8743, that is, close to 1 which shows high capability of the model for describing the changes and determiningthe areas prone to changes. A pictorial file was also extracted along with the model results through which the areas of urban developments can be anticipated in the future.Maximum-likelihoodcells for development are removed from the imagefile for each period in thefuture as the areas of urban development
5.Conclusion
These models are appropriate for anticipating the urban development location and making urban managers and authorities able to avoid uncontrolled urban development through suitable administrative strategies.
Land zoning around the city is suggested in order to keep valuable lands such as jungles and agricultural lands.
Keywords
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