Shirin Mohammahkhan; Hamid Ganjaeian; Somaieh Shahri; Amirali Abbaszade
Abstract
Extended Abstract Introduction Cities have always been under the influence of various factors and developed under such conditions. Countries around the world are increasingly moving toward urbanization. Physical development of cities occurs in the form of human activities or changes in urban (or rural) ...
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Extended Abstract Introduction Cities have always been under the influence of various factors and developed under such conditions. Countries around the world are increasingly moving toward urbanization. Physical development of cities occurs in the form of human activities or changes in urban (or rural) land use, and lead to widespread use of lands and adverse environmental effects. In some cases, urban growth leads to environmental hazards and threats human societies. Although the effects of natural factors such as geomorphological phenomena have not been scientifically considered in the development of the study area, there factors had a leading role in this development. Due to geomorphological situation, elevations and steep areas, scattered fault lines and rivers full of water, development of human settlements in the study area faces many constraints. Therefore, it is necessary to plan urban development in the study area based on the geomorphological situation of the region. Accordingly, the present study seeks to evaluate the trend of changes occurred from 1992 to 2017 in the residential districts of Marivan. It also aims to determine the extent of urban growth towards areas facing geomorphological hazards, and finally to predict this trend for 2035. Materials and Methods The present study takes advantage of an analytical and statistical research method, along with the necessary software. Moreover, it seeks to study the trend of urban development from 1992 to 2017, and also predict the future trend of development for 2035. Thus, satellite images received in June 1992, 2001, 2011, and 2017 are collected. After preprocessing the images, a land use map is extracted based on the situation of the study area in 1992, 2001. 2011 and 2017. Then, based on these maps and using effective variables, a map is produced based on the predictions made for the residential areas in 2035 by LCM model. Modeling and prediction are performed using LCM model in four steps: 1. Examination of Land Use Changes; 2. Mapping Potential Transfer using Markov Chain. 3. Extracting a predictive map. 4. Evaluating the accuracy of prediction. After predicting and extracting a map of residential areas for each time period, distribution of geomorphologic hazards in these areas is evaluated. In fact, development trend of high risk residential areas has been evaluated. Discussion and Results A large part of the study area is mountainous, and these elevations have somehow limited the development of human settlements. Since the present study seeks to determine the trend of human settlements development in areas facing geomorphological hazards, a map has been extracted for these prohibited areas before evaluating the trend of development. These prohibited areas have been mapped in order to identify hazardous areas, and to evaluate development of residential settlements toward these areas. To prepare this map, multiple criteria have been selected based on the situation in the region and experts’ opinion. Then in accordance with the purpose of this research, an information layer was produced using these criteria. Regarding geomorphology, regions with an altitude of more than 1700 m, slopes of more than 30%, north-south direction of the slope, area within 1000 m radii around fault lines and within 200 m radii around rivers are referred to as prohibited areas. After determining prohibited areas, human settlements in the study area were mapped based on 1992, 2001, 2011, and 2017 information. Then, trend of settlement development in prohibited areas was estimated and projected for 2035. Conclusion Based on the evaluation of results, there is an increasing demographic trend from 1992 to 2017, so that residential area has increased from 7.8 km in 1992 to 10.9 km in 2017. Maximum development occurred from 2001 to 2011. During this period, settlements developed 3.6 km2 and reached around 14.5 km2 in 2011. From 2011 to 2017, settlements area reached 16.6 km2. Apart from the increasing trend of development in residential areas during these years, this development has mostly occurred toward hazardous areas. So that in 1992, around 1.7 km2 of total residential area was located in prohibited areas, most of which included steeped areas and rivers’ border lines. In 2001 and 2011, this trend has increased from 2.3 to 2.9 km2, and reached 3.3 km2 in 2017. Considering the increasing trend of population toward Marivan, increased constructions in peri-urban and rural areas of Marivan and also along the main road of this city, development of settlements toward prohibited areas has mostly occurred in these areas. According to the main purpose of the present research, development of residential areas is projected for 2035 based on land use in pre-specified years. Results indicate that total area of settlements will increase to about 24.3 km2 in 2035, about 5.7 km2 of which will be in prohibited areas.
Kaveh Jafarzadeh; GholamReza Sabzghabaei; Shahram Yousefi Khangah; satar soltanian
Abstract
Extended abstract
Introduction
City has long been regarded as one of the human achievements by civilizations. Urban structure is part of the basic and mainconcepts of urban engineering knowledge and, in fact, is the foundation of its formation, and it is of great importance that some urban planners ...
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Extended abstract
Introduction
City has long been regarded as one of the human achievements by civilizations. Urban structure is part of the basic and mainconcepts of urban engineering knowledge and, in fact, is the foundation of its formation, and it is of great importance that some urban planners in developed countries regard it as equal to the spatial planning of the city. Today, lots of driving forces exert pressure on the environment. Change in land use and land cover is one of the pressures caused by driving factors such as population and its increase. The destruction of urban landscape, and change in land use and land cover are cases that constantly pressure the environmentof the country. Land use change is a complex and dynamic process thatinterconnect natural and human systems, therefore it directly relatesto many environmental issues that are globally significant. So, it can be stated that changes in urban structure has always been one of the most important factors, by whichmanhas influenced his environment. Given the role of environment in human life, precise information about the environmental change and the process of their changes should be achieved,which, can determine the extent of the expansion and destruction of resources, and guide these changes in appropriate courses by predicting urban structure changes.
Materials and Methods
In this research, an eight-year period ofthe Google Earth images from Digital Globe, Astrium satellites for the years 2007-2015 was used to model the changes of the urban structure in the study area. These images were then digitized to identify the desired uses. The required preprocessing was carried out by implementing the rules of topology, and the map of user changes for the two periods of 2007 and 2015 was prepared by inserting the images into the ENVE software, and land use was located in 12 educational, religious, park and green spaces, Residential, agricultural, gardens, industrial, sports, tree cover, wasteland and industrial land classes.Then, the transfer force modeling was carried out using the Perceptron of Multi-layer Artificial Neural Networks and 11 variables that include slope, direction, elevation, distance from residential areas, distance from agricultural lands, distance from the gardens, distance from the water zone, distance from the tree cover, distance from barren lands and distance from the road. Then, theassignment of changes to each use was calculated using the Markov Chain, and the modeling for the year 1402 was carried out using the hard prediction and calibration periodmodelofthe years1386to1394.At the end, the urban structureof 1402 was predicted using the Calibration period of 1386 to 1394.
Results and discussion
The results of monitoring the changes showed that agricultural uses (437) and tree cover (9) have decreased, while other uses have increased during two study periods. The reasons for these changes can be largely due to the increase in population and the increase in the needs of the population along with the agricultural not being cost effective, and the roads, wastelands, gardens, educational, religious, water zones, parks and green spaces, industrial, sports and residential uses have had an increasing trend. The results of modeling the transition forceusing artificial neural network showed high accuracy in most of the sub-models. The total error in modeling was obtained for the year 1394, which illustrates the high adaptability of the projected image of the model with the image of the ground reality and the acceptability of the model.The results of modeling for the year 1402 indicatea very high increase in the use of residential (195 hectares) and garden (104 hectares), and a significant reduction of 33 hectares in agricultural use.
Conclusion
In general, it can be stated that the trend of Changes in the urban structure ofGhaemshahr, especially in agricultural and residential sectors is enormous, which leads to the degradation and destruction of the natural environment and the fragmentation of communication corridors that guarantee the balance and sustainability of wild life and the environment. All of these factors are due tothe poor urban and environmental management, including control, supervision and monitoring and the lack of proper planning. The findings of this research call for the necessity of more attention to the sustainable exploitation of the land and preventing its destruction in this city. The results obtained from the prediction of the future also indicate the reliability and validity of the model that is fully consistent with the reality and can be used as an executive model in the future vision planningfor the city ofQaemshahr, and it is possible to prevent damages to the city and its nature through proper urban planning and decision-making of managers.
Mohammad Rahim Rahnama; Mohammad Ajza Shokouhi; behnam ata
Abstract
Extended abstract Introduction Cities are always influenced by various forces and factors. They are transformed by social changes, demographic displacements, economic changes, and technological innovations. As the population grows, activities and investments are greatly expanded and the ...
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Extended abstract Introduction Cities are always influenced by various forces and factors. They are transformed by social changes, demographic displacements, economic changes, and technological innovations. As the population grows, activities and investments are greatly expanded and the physical system of the cities undergoes fundamental changes.Along with the rapid urbanization process, a large amount of natural lands, such as forests and wetlands, has turned into agricultural land and residential areas. Quick land use changes have had profound effects on natural and human environments. For example, agricultural developments and structures lead to deforestation, soil erosion, water basin degradation, and biodiversity loss and pollution. In addition, changes in the use of agricultural land and the acceleration of urbanization have led to an increase in impenetrable levels, which has led to the development of a transport network and the accumulation of non-disturbing contaminations associated with surface runoff. Due to these great effects, the detection and anticipation of land use changes has become an important topic in environmental management and land use planning. At their initial stagesof formation, most of the cities in Iran were established near or in the middle of thehigh-quality agricultural lands with the purpose of using high-quality soil foragriculture and then, these lands were gradually buried under the cities throughdevelopment of villages and changing into cities and then development of thecities. Accordingly agricultural activities were inevitably receded to the poorlands. Materials & Methods To access fundamental maps for analysis of data and use of different methods to achieve the goal of this study, satellite images related to the years 1987,2000 and 2010 are used. Topographic maps of 1:50000 scales obtained from the army geographical organization are used for geometric correction. At this stage, geometric correction was performed on the images using image sensor TM of the year 2010 image-vector, which were geo-referenced. To perform this task, 42ground control points with appropriate distribution in road junctions, water channels, etc. were used. In this research, to process data, make models, and analyze the output, land cover maps produced in the years 1987 and 2014 as inputs of the LCM model, were selected to analyze the changes in the region and predict land use changes in the year 1404. The LCM model requires two maps covering lands belonging to different times as inputs. In this study, Gains and losses, net changes, unchanged regions, transitions from each user to another in different classes of land cover, were mapped to the model analysis section of the model.ENVI, IDRISI Selva and ARCGIS10 were used to categorize the uses of most-probability-models and methods and finally Ca_Markov model was used to predict and calculate changes in 2025, 2035 and 2045. Results & Discussion Multi-temporal images used in this study were used in mapping land coverafter geometric corrections. With regard to existing images and maps and the condition of the area under investigation and field visit for mapping land cover, five types of applications are discovered for land namely, residential lands,irrigated lands, rain-fed lands, sterile lands, parks and gardens. Altogether, during this time (27years), agricultural and residential land cover has increased and sterile land and rain-fed land cover has decreased. Agricultural lands consume a huge amount of water due to exploiting water from deep holes and land overuse that has turned rain-fed lands and sterile lands into water-fed and residential lands. As the table of predicting areas indicates, the greatest increase of about 1744/74 hectares belongs to agricultural lands and 1741/79 hectares belong to the urban lands which includes: residential lands, trade centers, military areas, hospitals, higher education institutes, etc. The least change which is 274/18 hectares, belong to parks and gardens in and around the cities. The most decline of 2261/59 hectares, is observed in sterile lands. Of the total net changes, one can conclude that urban use has increased and all land cover has become largely urbanized, as well as water lands with the rise and development of deep wells. The need to preserve these lands from the physical development of the city in this direction is essential in order to develop the sustainable development of the city. There are many undeveloped lands in the old days due to the lack of water and the lack of facilities. The advancement of agriculture, turned these lands into agricultural lands. Today, landless areas are mostly on the suburbs or around the cities. This is mainly because of the farmers who leave their lands in a state of desert in hope of urban development to gain huge profits.This is the case where the city of Gonbad-e-Kavoos is not an exception to this rule. Parks and Gardens also have a rational increase in the city, therefore, in urban development projects, parks have been created but the size of the gardens is very low in the city of Gonbad-e-Kavoos. By predicting the changes in usages, it is concluded that the most changes will take place in urban usages and rain-fed and sterile lands with dramatic increase and decrease respectively.As the population of the city of Gonbad- e-Kavoosgrows, some steps should be taken to develop the spatial area of the city so as to prevent the destruction of fertile lands for the sake of human construction. Conclusion In this study, the effect of physical expansion of Gonbad-e-Kavoos city on agricultural lands is investigated. Findings indicate that during 45 years, around 1880 hectares of fertile farmlands surrounding the city are destroyed. The main reason behind this destruction is the horizontal expansion of the city. Hence, one of the fundamental bases of sustainable urban development is the increase of city density. It is concluded that horizontal expansion of the city is totally in contradiction to sustainable development and it leads to more instability of the city.
