Geographic information systems (GIS)
From 1980's application of GIS has been largely expanded so that in developed countries, most universities, commercial organizations and governments use these systems for different purposes. Based on the application of GIS, spatial operation in a geographic information system and the possibility of spatial analysis of the features and the relationship between them based on the geographical coordinates, the GIS has been developed in different parts according to the needs of each region and country. Also in Iran, during the last decade, GIS has been used vastly for identification of resources and management of urban and environmental projects. But the practice of analyzing the development models by using GIS in urban development planning is a new experience.
Presenting an urban development model for North-West of Tehran by using GIS and RS for analysis & planning
In advance to presenting an urban development model, the results of satellite images processing related to the main land use changes in the North-West of Tehran (district22) are presented aiming to study the past and the process of changes and then proper models for development by using environmental models are presented .
By using the extracted results from satellite images and RS technology and by comparison of the main land use changes in the city of Tehran during the recent years, the most important amount of changes in physical specification and conditions of Tehran such as water conditions, open areas, gardens, fields, green areas, and installations and buildings during the years 1984 to 1998 are extracted by using Land Sat TM-7 images.
The statistics reveals a noticeable reduction of farm lands and gardens in district22 of Tehran which can be quite effective in overall physiognomy of the district .The other fixed natural resources of the district too, have been overused so that it has resulted to environmental destruction of the area .This means the expansion of urban limits and so the destruction and reduction of natural resources and open areas of the district while such natural resources and open areas are of great importance in an urban management system.
The amount of residential areas during a period of study shows a 15% growth while there is no growth in the amount of green areas.
The amount of farm lands and gardens have been declined and open areas and lands have been reduced, therefore we can conclude that most of the constructions have been in open areas and some in place of gardens.
In addition, by using satellite images have provided a chart of geographical changes and conditions of the district have been provided which are presented on the base of comparison.
In the presented urban development model, at first, the ecological potential of development of the region has been provided.
By using the digital map of Tehran, coordinates of specific points which could be identified in satellite images and maps have been extracted.
Geometrical corrections, for image to map adjustment have been done by PCI software.
It should be considered that number and dispersion of the points for geometrical corrections have been studied and adjusted according to technical specifications of the work and10 locations in the region of Tehran have been used.
All the necessary preprocessing in order to improve the quality of images such as: contrast enhancement, filtering and fusion have been done before data processing.
Also the combination of data related to digital maps of the district have been applied for adjustment and correction of satellite data. Geographical and water networks, political boundaries and population centers, transportation network, elevations, topographic lines and names of the locations are extracted from the maps of the district and used for combination of data and expressiveness of the image in order to identify the region.
By using the supervised classification method, the result of changes in land use for a defined period of time is calculated and extracted and presented in a table.
The results are used for study of physical changes of city and then; in the phase of analysis, by using GIS for land use planning.
Statistics related to land use changes (per km2) between 1984 to 1998 of district22 (North-West) of Tehran (Land Sat-TM) Satellite images
| Year |
Residential |
Non residential |
Green zone (public) |
Green zone (private) |
Farms/gardens |
Open Lands |
Water |
| 1984 |
2.07 |
6.05 |
9.38 |
2.38 |
3.53 |
88.81 |
0.23 |
| 1994 |
3.71 |
6.75 |
9.41 |
1.94 |
3.19 |
86.79 |
0.23 |
| 1998 |
4.00 |
6.82 |
9.41 |
2.34 |
3.2 |
86.43 |
0.23 |
To present urban model, the ecological specifications of Iran and the region have been studied and then assessed and classified. Then through comparison, and by considering the specifications of studied area the model is provided and the best locations for urban development with residential and administrative application, recreational application, industrial and workshop application and athletic and cultural application are determined and then presented as maps in GIS.
To provide and present urban development models, the studies that have been made during the last 30 years are used and the made model is applied for determination of the best potentials of the land and having the optimal ecological parameters for assessment of urban development. That can used in GIS in order to analyze the data and assess the ecological potentials, Some of the simplified conceptual models are brought at the end of the paper.
At the same time, a lot of basic studies have been used to improve the quality of the models. These studies are wide and with different aspects. The made models have also the capability of inversion into geographical, mathematical and conceptual models too which some of them have been presented in the paper.
As the North - West region of Tehran which is case of study has been included in urban development projects in some parts, all standards and operational regulations of Iran in conservation of environment have been considered in the model for extracting the final applications of each location.
Some of the sources and researches that have been used for presenting the model of urban development are as followings:
- Ecological model of urban, rural and industrial development of Iran.
- The executive procedures and regulations of new comprehensive development project of Tehran (Executive regulations for conservation of environment )
- The urban development suggestions presented by the Center of Studies and Researches of Ministry of Housing and Urban Development.
- The qualitative standards in urban development provided by the Urban Planning Studies Group of Ministry of Interior.
- National physical Plan of Iran and the research of development possibilities of water resources and distribution of population.
- The data available in national atlas of Iran, atlas of environment and atlas of urban planning.
- The extracted data from the studies of Geological organization of Iran.