Abstract

Landscape arrangement significantly influences observer’s visual experience of the environment. Since measuring this qualitative experience is more based on personal judgments than mathematical techniques, representing “quantifying methods” in this field demands a significant amount of caution and accuracy. This research is an attempt to quantify visual impacts of seven-story- and higher-buildings on observers’ view of Tehran’s district 3 from 1993 to 2006. For this purpose observers’ visibility of the surrounding landscape was calculated for 17 random points of the region, at 1.5 and 10 m, before and after construction of towers in that period by use of Geographical Information System (GIS, Arcmap V.9.2). The result of this research indicates that visibility of citizens of Tehran has decreased from 13% in 1993, after construction of 12 towers, to 45% in 2006 after construction of 255 towers. The objective of this research was to assess the visual impacts of structures on landscape and to attempt to clarify the necessity and importance of applying Visual Impact Assessment (VIA), among other environmental assessments in new urban developments.

Key words: Landscape, geographic information system (GIS), viewshed, visibility, building, regional planning, visual impact assessment.