Istanbul experienced significant changes in its urban pattern as a result of Westernization that took place in the nineteenth century. Galata, a neighbourhood located in the Beyoglu District, represents the occidental and cosmopolitan face of the city during that time. This study examines the spatial effects of these social and political changesby integrating old city maps of Beyoglu and Galata with geographic information system programmes (GIS). This methodology affords novel interpretations of historical maps thanks to these new ways of analyzing, displaying, and managing geographical information. The maps of G. d'Ostoya (1858-1860), R. Huber (1887-1891), and Charles E. Goad (1904-1906) have been coordinated with GIS software. Items such as buildings, roads, and empty spaces included as raster data have been transformed into vector data to make comparisons and superpositions possible within the GIS environment. Thus, the transformation of urban space can be revealed, and conclusions about how Galata experienced broader change across the nineteenth century can be perceived.