Urban Scape
Mohammad Azad Ahmadi; Mehrdad Karimi Moshaver
Abstract
Today, the issue of visibility assessment and visual impact (dominance) of a building on its surrounding context is considered as one of the most important issues of urban landscape. Accordingly, this paper analyzes the visibility of two high-rise buildings in the center and west of Sanandaj using raw ...
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Today, the issue of visibility assessment and visual impact (dominance) of a building on its surrounding context is considered as one of the most important issues of urban landscape. Accordingly, this paper analyzes the visibility of two high-rise buildings in the center and west of Sanandaj using raw input data and processing them by GIS and ArcGis 10. For the visibility analysis in urban landscape, the mutual visibility between high-rise building and its surrounding area is calculated. This is done traditionally by taking photos from urban areas. However, in this method, the whole region is studied by considering all points and places. The available vegetation such as trees with an approximate transparency ratio is considered to obtain more accurate results. Also, for better evaluation of differences between the amount and trend of visibility, the areas around both buildings (region number 1 is relatively flat and has a river-valley with low depth and mild slope; region number 2 involves dune hills) were classified into the close, intermediate and far fields. The visibility of these two high-rise buildings in their surrounding areas is in the form of output GIS images which is calculated separately for both buildings and all their floors. It means that for building number 1, which has 17 floors, 17 output maps of visibility to surrounding areas are obtained by the software. Also, for building number 2 with 14 floors, 14 output visibility maps are obtained. The findings show that visibility trend of different floors of these two buildings is not a constant and linear trend, it has variations in some points. Among these points, visibility and its effect, relative to surrounding areas, is more important than other floors in the triple fields. The points where visibility curve has track change, steep change and sudden increase show the greater importance of their visibility and their relative dominance than other floors. These floors can visually have more effect on their surrounding environment. Therefore, the design style of these particular floors (milestones in the visibility curve) in high-rise buildings can be important. The changes in floors visibility trend and their values were different for the two buildings. By evaluating the related diagrams, the reasons for this difference were found in three cases: first, the difference in average height of buildings around of two buildings; second, the difference between the tilt around the two buildings; and third, the dune hill in region number 2. Finally, we can say that visibility analysis is considered to be a tool for modeling the visibility in planning high-rise buildings. Before constructing such buildings, visibility analysis can be an effective method to estimate that a floor or an apartment will or will not have a good view after completion. Therefore, this tool can be used to investigate the positive or negative value of a region. Also, the extent to which a building is or is not visible can be very important in decisions about determining the height of a building relative to its surrounding texture (especially in cities with historically valuable texture and touristic landscape).
Urban Design
Amir Shakibamanesh; Yasaman Hakimi
Abstract
One of the main issues in visual analysis of urban spaces is their visibility. It is one of the main research interests in recent urban studies due to the development of technology and digital software. The results of most recent studies suggest that the physical visibility of urban spaces is closely ...
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One of the main issues in visual analysis of urban spaces is their visibility. It is one of the main research interests in recent urban studies due to the development of technology and digital software. The results of most recent studies suggest that the physical visibility of urban spaces is closely connected to the possible behaviors occurring in them. Due to the fact that there are many different issues affecting different conditions of visibility and subsequently the perception of people, this article focuses specifically on urban squares to obtain more scientific and accurate results. In particular, having all the features of an actual urban square, the Sabzeh Meydan square which is located in the central area of Tehran is chosen as the case study. This square is visually analyzed by applying 3-dimensional isovist concept and studying its relation to other variables of population behaviors such as “pause and movement”, “individual and social behaviors” and “flow’s pace” considering the sex variable. For this purpose, the visibility map of the area was produced in GIS software and the relationship between the main variables of the study was examined by statistical analysis and correlation coefficients in SPSS.This study clearly showed that visibility was associated with behavioral patterns and affected the groups using spaces. The results indicated that women preferred to pause in places with moderate visibility. In fact, what they prefer is that the place where they pause should not have a weak or a high visibility. On the other hand, the findings showed that men were more likely to pause in places where visibility was more than other parts. The findings also showed a significant relationship between pause and motion behavior patterns and visibility, but the significance was not strong. Based on the statistics, pause behaviors are most likely to occur in places with more visibility and movement behaviors occur more in places where there is less visibility. People prefer to stay and pause in places which provide more functionality for viewing the surroundings. Other results of this study showed a significant relationship between individual and social behaviors and visibility level. This relationship was stronger than that in other cases. Statistics indicated that social behaviors were performed in places with a better visibility than other places. Field observations also showed that when the level of visibility decreased, individual behaviors outweighed social ones. In this research, the relationship between social and individual behaviors in sitting places and visibility level was also studied. The findings showed that the sitting places where most individual behaviors occurred were often located in areas with relatively good visibility levels. The results of studying the relationship between velocity and visibility level showed a significant relationship between the two variables. This means that as the visibility of a space increases, the speed of movement decreases. Based on field observations, it can also be said that people travel faster in environments with less visibility. Therefore, in urban spaces where people’s speed should decrease, visibility should increase compared to other urban elements.
