Measuring environmental quality of life : a GIS approach to deriving objective measures using Hong Kong as a case study

Abstract

Quality of life (QOL) is a comprehensive concept used to assess a society’s standard of living in all aspects of life. A significant part of the QOL assessment involves subjective measures about feelings of satisfaction and happiness, as well as related attitudes which can be easily affected by personal views and cultural differences. The increasingly globalised economy has made it necessary to have objective QOL measures that can be applied consistently to make comparisons among different geographic space. QOL is multi-dimensional in nature and often involves social, economic and environmental measures. The social and economic aspects have been examined widely by objective and subjective means. This research aims at exploring the environmental aspect of QOL, particularly in reference to geographic information systems (GIS) and remote sensing (RS) technologies, to derive objective indicators suitable for Asian cities where the world’s most rapid economic growth and urbanisation are happening.

The research was conducted in Hong Kong and 89 well-spread neighbourhoods representing different degrees of urbanisation were delineated as the study areas. The spatial unit of a neighbourhood was fixed at 800m x 800m cell for consistent and meaningful comparison. GIS and RS were used to extract (from digital maps, aerial photographs, and satellite images) urban morphological characteristics at the neighbourhood level. Four domains of built environment at the neighbourhood level were identified: (i) education-health-recreation facilities, (ii) local street network, (iii) compatible land use diversity, and (iv) building footprint intensity. Their respective indicators were obtained either from official resources or derived using GIS and RS methods.

The methodology employed Principal Component Analysis to reduce the dimensionality of each domain into a single score. These domain scores were instrumental in grouping neighbourhoods with similar characteristics using the hierarchical clustering method. An environmental quality sub-index (EQ-I) can be computed by aggregating domain scores that have been adjusted by standardisation procedures and weighted, if desired. Regional variation of neighbourhood environmental quality can be examined visually using radar charts. The potential utility of the EQ-I was compared against the well-established social deprivation index (SDI) of Hong Kong and its ability to accommodate additional domains was also tested. It was found that the EQ-I did not yield ratings similar to those of SDI which indicate that the two indices do not measure the same metric. Although the additional domains did alter the rank order of neighbourhoods, the shifts were made in accordance with the contributing power showing the stability of the approach.

Despite the environmental domains selected in this research were not all inclusive, the study did illustrate a methodological approach to collapse and combine multiple variables into a single sub-index. Indeed, the statistical approaches including factor and cluster analyses provide useful means to address the multi-dimensional and complex nature of environmental quality. The resultant scores provide simple, direct and objective measures that are replicable to other settings or cities to render international comparison.