Analysis of urban growth in coastal areas supported by 2D/2.5D GIS data. A comparative study of Boa Viagem Beach (Brazil) and Rocha Beach (Portugal)

The coastal areas, as a place of interaction between terrestrial and marine systems, are environmentally sensitive and, in recent decades, have undergone constant transformation primarily due to human intervention. Subject to great real estate pressure, the natural landscape (the birthplace of complex ecosystems) has been substantially developed, serving the purposes of different socio-economic interests. This modification of the natural landscape is reflected in the expansion (in area) and densification (in volume) of built-up areas, accentuating the trend towards the vertical growth of cities. The objective of this paper is to analyse the vertical growth of coastal built-up areas of Boa Viagem Beach (Brazil) and Rocha Beach (Portugal) during the period 1940–2013. The analysis considers three different dimensions of vertical growth: urban-physical, socio-demographic and political-urban. For this purpose, we used quantitative methods and techniques, supported by 2D/2.5D GIS data. This methodology overcomes the challenge of obtaining quantitative three-dimensional information across a broad time period and allows for the comparison of the development pace in two different countries. Rhythm and volume are correlated with events of national and local impact. The comparison between the two countries reveals substantial differences in the design and implementation of the planning system and land management instruments but, on the other hand, shows interesting time parallels in the phenomenon of vertical growth. Results indicate that development is strongly influenced by the social, political and economic oscillations of the globalized world. We conclude that the main factors driving urban growth in both study areas are internal and external factors, which are strongly associated with political and economic stability. This correlation turns clear that political and economic stability play an important role and have a direct influence on urban development. This work contributes, through a 2D/2.5D GIS approach, to an integrated understanding of the vertical growth processes in intensively built-up coastal areas. The essayed methodology demonstrates that the methods and techniques are flexible enough to be replicated for the analysis of other coastal cities around the world.