Measuring sky view factor of urban canyons using hacked Gopro hemispheric video processing

  • YEAR
    2015
  • AUTHORS
    White, Marcus
    Kimm, Geoff
  • CATEGORIES
    2015 Conference Papers
    Built Environment Performance Assessment
    Conference Papers

Extract

Increased urbanisation and densification is producing urban fabric with increasingly deep ‘urban canyons’, trapping longwave radiation and contributing to the Urban Heat Island (UHI) phenomenon. With global temperatures along with heat related mortality predicted to increase, there is a critical need to understand urban canyons and heat retention in cities. Methods for analysing urban canyon through Sky View Factor (SVF), an established contributing parameter in the prediction of UHI, have until now been limited to relatively manual, time intensive calculations using individual points of assessment from still photographs. This paper describes a method for rapidly capturing the extent of urban canyon enclosure by way of mobile video SVF processing. A lightweight GoPro™ video camera was hacked to capture on-the-go 180° hemispherical (fisheye) video. This video was analysed using our custom pixel-based image processing tool calculating SVF. This SVF analysis was synchronised with logged GPS, air temperature, humidity and light levels data captured by linked Bluetooth sensor and smartphone to record city wide urban canyon and atmospheric longitudinal cross-sections. The approach is inexpensive and has potential for continuous, detailed, city wide data collection by mounting on public transport. This investigation provides a new, rapid analysis tool for urban researchers enabling further study of the relationship between urban heat retention and urban form.

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