Personalising the viewshed: Visibility analysis from the humanperspective

Type of content
Journal Article
Publisher's DOI/URI
Thesis discipline
Degree name
Publisher
University of Canterbury. Geography
Journal Title
Journal ISSN
Volume Title
Language
Date
2015
Authors
Nutsford, D.
Reitsma, F.
Pearson, A.
Kingham, S.
Abstract

Viewshed analysis remains one of the most popular GIS tools for assessing visibility, despite the recognition of several limitations when quantifying visibility from a human perspective. The visual significance of terrain is heavily influenced by the vertical dimension (i.e. slope, aspect and elevation) and distance from the observer, neither of which are adjusted for in standard viewshed analyses. Based on these limitations, this study aimed to develop a methodology which extends the standard viewshed to represent visible landscape as more realistically perceived by a human, called the 'Vertical Visibility Index’ (VVI). This method was intended to overcome the primary limitations of the standard viewshed by calculating the vertical degrees of visibility between the eye-level of a human and the top and bottom point of each visible cell in a viewshed. Next, the validity of the VVI was assessed using two comparison methods: 1) the known proportion of vegetation visible as assessed through imagery for 10 locations; and 2) standard viewshed analysis for 50 viewpoints in an urban setting. While positive, significant correlations were observed between the VVI values and both comparators, the correlation was strongest between the VVI values and the image verified, known values (r = 0.863, p = 0.001). The validation results indicate that the VVI is a valid method which can be used as an improvement on standard viewshed analyses for the accurate representation of landscape visibility from a human perspective. Highlights  Standard viewshed analysis is a poor measure of visibility from a human perspective.  A novel method (VVI) was developed to represent visibility from a human perspective.  The VVI demonstrated predictive validity for known environment visibility (r = 0.863, p = 0.001).  The VVI is a valid novel methodology for improving viewshed analyses when visibility from a human perspective is the focus.

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Citation
Nutsford, D., Reitsma, F., Pearson., A, Kingham, S. (2015) Personalising the viewshed: Visibility analysis from the human perspective. Applied Geography, 62, pp. 1-7.
Keywords
visibility analysis, viewshed, environment visibility, environmental health, GIS
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Field of Research::04 - Earth Sciences::0406 - Physical Geography and Environmental Geoscience::040699 - Physical Geography and Environmental Geoscience not elsewhere classified
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