Measuring spatial - temporal of Yazd urban form using spatial metrics

Urban form can be affected by diverse factors in different times. Socio- economic, political and physical factors are among the main contributors. So, one of the most important challenges of urban planners is measuring and identifying urban development pattern in order to direct and strengthen it to sustainable pattern and right direction. The case study of the present paper is the city of Yazd, a middle-sized city in the center of Iran, and the studied years are 1975, 1987, 2000 and 2010. To achieve the main objective of the paper, measuring Yazd growth and expansion by spatial metrics, it has used remote sensing data and satellite imageries and ArcGIS software. The conclusion revealed that in four periods of study, complexity or irregularity of the urban patch shapes has increased, centrality or average distance of the dispersed parts to the city center has decreased, compactness or the number and area of patches their distance from each other has decreased, porosity or ratio of open space has increased and finally population density of city has decreased in a large amount. Therefore, all perimeters show that the temporal - spatial form of Yazd has moved from compact to sprawl. Due to many undesired impacts of urban sprawl, urban planners and authorities are required to use adherent techniques and policies to control urban sprawl and to direct it toward more sustainable directions.