The integration of GIS into demographic surveying of informal settlements: The case of Nelson Mandela Bay Municipality, South Africa

A number of informal areas in Nelson Mandela Bay Municipality, South Africa have experienced rapid expansion over the past decade. Census data available for these areas is outdated and does not provide enough information for local authorities to plan tasks such as service delivery management and resource allocation. In this study, a GIS based demographic study of informal settlements within Nelson Mandela Bay was undertaken. The study aimed to significantly improve the collection, analysis, interpretation, display and management of demographic survey data and provide the accurate and necessary updates required between census collections. Data relating to informal settlements were captured from 1996 aerial photographs and 2007 satellite imagery, and demographic data were collected from field surveys. Specific demographic trends identified through spatial analyses included a 71% and 109% decline and increase in informal and formal dwellings respectively. A significant increase in backyard shacks paradoxically came with the development of many formal structures in settlements. The capture and collection of data at household level and creation of customized boundaries for informal settlements facilitated analyses independent of any fixed set of areal units. The study concluded that GIS based demographic studies are vital for providing the necessary updates to decennial censuses for municipalities, particularly in urban environments of developing countries. •A GIS based demographic study of informal settlements is undertaken.•A large decrease in the number of informal dwellings is discernible.•Despite the increase in formal dwellings, backyard shacks increased by 117%.•Regular updates on informal dwellings are of importance to local authorities.