Street enclosure overview
Summary of indicator
To measure the relationship between building height and street width, and explore the visual definition of a street.
A sense of enclosure / openness contributes to the character and comfort of a street or area. A street aspect ratio that falls within the desirable range provides an environment that is at the appropriate human scale and influences a user’s sense of comfort and safety in urban areas. It is also associated with climatic performance indicators such as shading, whereby higher enclosures tend to indicate less solar exposure and sky visibility on the ground plane, and wind, the effects of which can be accentuated in spaces with a high SAR.
This indicator will support practitioners to understand the character and built form in urban and metropolitan areas. Based on the outcome of the assessment, practitioners can determine whether the visual field is appropriately enclosed based on the surrounding land uses.
Practitioners can use the Street Aspect Ratio (SAR) metric to measure the ratio of the average height of buildings to the width of road segments.
Street Aspect Ration (SAR)
- To enrich the analysis, Sky View Factor could be incorporated. Sky View Factor is best represented as a fish-eye photograph of the sky from the street, with values ranging from zero to one. When obstacles block the sky, the factor goes to zero. When the sky is completely visible, the factor is one
- Building density along the road could be considered in the analysis.
Metric in detail