An analysis of spatial development tendency of Istanbul

Urban spatial structure is increasingly characterized by decentralization, dispersion, concentration, and multiple centers. In Istanbul, dual development processes have been observed in the course of time. The first process is continuous urban expansion with low density development which was triggered mainly by squatter settlements at the periphery and recently occurring high density mass housing development due to low land values. The second process is the intensification and/or renewal process within built-up areas in the central parts of Istanbul. In this paper, density and land value gradient analysis has been used to analyze urban structural change in terms of core-peripheral relationship in Istanbul. A GIS database is set up to obtain density, land value, distance measures, visualize spatial patterns, and calculate density and land value gradient. In general, standard urban models predict a pattern of negative exponential density gradients within cities, where there is a gradual decline in population density and land value from the center of the city to its outskirts. In the Istanbul case, negative exponential density and land value gradients is observed even though Istanbul has the changing urban structure from monocentric to polycentric. Furthermore, the fact that the change in land value at peripheries has been higher than that of the central zones and the increase in density changes at peripheries shows that the macro-form of Istanbul has demonstrated both urban expansion and urban intensification characteristics from past to present.