Impact of Urban Forms on 3d Built-Up Intensity Expansion Rate from Aerial Stereo-Imagery
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Date
2020
Authors
Mwangi, P. W.
Karanja, F. N.
Kamau, P. K.
Letema, S. C.
Journal Title
Journal ISSN
Volume Title
Publisher
The International Society for Photogrammetry and Remote Sensing
Abstract
Urban areas have been cited to be contributors to changing climatic conditions. Conversion of vegetated areas to impervious surfaces causes
an alteration of surface temperatures, where impervious surfaces absorb and store incoming radiation during the day, releasing it slowly at
night. This causes the urban heat island effect where temperatures in urban areas are higher than rural areas during night. Extreme weather
conditions experienced in urban areas include heat waves, intense rainfall resulting to flash floods, destruction of infrastructure facilities.
The research involved the use of time-series of stereo-aerial images acquired in 1978, 2000 and 2017. Building footprints were digitized
and using digital elevation models, building heights were derived and volumes calculated. Road volumes were calculated using minimum
standards of road construction and the total built-up volume was determined. The ground coverage ratio (GCR) and built-up volume
densities (BVD) of the built-up areas was calculated from area and volumes from road and building values. Results indicate the mean GCR
and BVD in Upper Hill is within the low density range. Mean building height from 1978 to 2017 are in the low-rise range with significant
rise in building height and volumes between 1998 and 2017. The 3D built-up intensity expansion rate ranged between -4.28% to 56.80%
per annum with a mean of 19.6% per annum. Roads and pavements also have a significant influence on the built-up density and should
therefore be considered in planning policies.
Description
A research paper published in ISPRS annals of the photogrammetry, remote sensing and spatial information sciences
Keywords
Ground Coverage Ratio, Built-up Volume Density, 3D Built-up Intensity, Height, Stereo Imagery, Urban Form
Citation
Mwangi, P. W., Karanja, F. N., Kamau, P. K., & Letema, S. C. (2020). IMPACT OF URBAN FORMS ON 3D BUILT-UP INTENSITY EXPANSION RATE FROM AERIAL STEREO-IMAGERY. ISPRS Annals of Photogrammetry, Remote Sensing & Spatial Information Sciences, 5(4).