Internal lands suitability evaluation for interior development in Gorgan city with using AHP & GIS

Land is the most crucial factor for physical growth and development of cities.Currently, land management has become one of the most important concerns and subjectsunder discussion for local governments.Moreover, growth and scattered development of cities has led to the destruction of the environment and natural resources of the suburbs. It is well known that urban sprawl is manifestwhen the growth of population is less than the growth in physical development.In fact, the main factor in urban sprawl development is population growth in addition to the demand for land for the purpose of housing, buildings, public land-use and their facilities. Meanwhile, as a result ofinappropriate andhastydecisions, land capacity in and on the outskirts of cities for developmentorre-development, have been ignoredby city managers. Today, interior and infill development is an important issue in new urbanism. Infill development emphasizes the development of brown and gray lands, reformation, renovation and reconstruction of existing textures.Accordingly, in the past four decades, Gorgan city has rapidly expanded within the city and on its outskirts from 997 hectares in 1974 to 3560 hectares in 2004; this has caused the destruction of natural environment of the area. Therefore, the purpose of this studyis the discernment and identification of suitable landinGorgan city for infill and re-development. Thisis an applied research and the method used is descriptive-analytical. For this purpose, analytic hierarchy process (AHP) as a multi-criteria decision making (MCDM) model was used for ranking, weighting and determination of the consistency ratio of the criteria. In addition, geographic information system (GIS), as a powerful instrumentation in environmentalplanning and management, was used for processing and overlaying of layers. Duration this process, 14 effective criteria and indexes including topography, slope, aspect of slope, landslide,fault vicinity, river limits, urbanland-use, size of parcels, floors of buildings, density of residential unit, zoning, density of population, price of lands and old texturewas identified, prepared and used in the form of environmental, physical and social indexes. Initially,criteriaandsub criteria(layers) was prepared by the formation ofa matrixusing hierarchical analysis, weighting andranking. Then, criteria and sub criteria (layers) was presented, geo-referenced, digitized, updated, standardized, edited, overlaid, processed, converted to raster and vector using geographic information system.Hence, the prepared layers (criteria and sub-criteria) with the extension of spatial analysis and raster calculator operator were overlapped ArcGIS software. Eventually, a final map of weightedcriteria and sub criteria (layers)was provided usingmathematical operation and weighted overlapping in ArcGIS software to identify suitable and compatible lands for interior and infill development of Gorgan city in response to the demandsof its citizens for buildings and housing. The final map suggests that the most suitable and compatible lands for infill and redevelopment are located in the north and north-eastern parts of the city; and the least suitable and compatible lands are situated south and south-western areas of the city and along river limits. Furthermore, it was determined that 51 percent ofinterior lands are completely compatible, 14.5 percent are compatible and 16.2 percent are relatively compatible, 12.2 percent are incompatible and 6 percent are totally incompatible for infill and redevelopmentin Gorgan city.