From Horizontal to Vertical Urban Growth: A Decade of LULC Change in Penang Island, Malaysia
Nur Faziera Yaakub (a*), Mohd Hasmadi Ismail (b) & Azita Ahmad Zawawi (c)

a) Department of Forestry Science and Biodiversity, Faculty of Forestry and Environment
Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
*sdgisfaziera[at]gmail.com
b) Department of Forestry Science and Biodiversity, Faculty of Forestry and Environment
Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
c) Department of Recreation and Ecotourism, Faculty of Forestry and Environment
Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.

Abstract

Urban growth is conventionally defined by spatial expansion and the increase in built-up areas. This study, however, reveals a counterintuitive trend in Penang Island, Malaysia, between 2014 and 2023. Utilising 1.5 m pansharpened SPOT 6 and 7 satellite imagery classified with a Support Vector Machine (SVM), we analysed spatiotemporal changes in land use and land cover (LULC). Our findings indicate a decline in built-up areas, a stark contrast to the official Department of Statistics Malaysia (DoSM) figures, which show a significant increase in population. This paradox challenges traditional urbanisation patterns, necessitating a more in-depth examination of the underlying spatial, spectral, and socio-economic dynamics. We explore several plausible explanations: vertical urban densification through high-rise development, urban redevelopment cycles involving temporary demolition, and policy-driven land-use conversions towards green infrastructure for enhanced liveability and climate resilience. Furthermore, technical limitations in remote sensing, such as spectral occlusion from dense vegetation or shadows, were identified as potential contributors to classification errors, validated through fieldwork and ground truthing. These findings highlight the critical need for a multidimensional understanding of urbanisation, moving beyond mere horizontal expansion to encompass vertical growth, redevelopment lag, spatial constraints, and policy-driven transformations. This analysis is situated within the context of Sustainable Development Goal 11, the New Urban Agenda, and Malaysia^s National Physical Plan Thrust 2, which advocates for a more holistic approach to sustainable urban development.

Keywords: LULC change, remote sensing, vertical urban growth, densification, sustainable development

Topic: Topic B: Applications of Remote Sensing