Imagery
The sourcing of imagery resorts under the geodatabase section in the Geography Division.

The geodatabase section forms the backbone for Geographical Information System (GIS) operations in support of other sections within the Geography Division.

GIS implementation and maintenance are the main focus areas and includes responsibilities such as spatial data collection, maintenance of an operational GIS and the development and implementation of GIS applications.


Imagery is applied for the following purposes:

  • Dwelling frame creation and maintenance: This implies the capture of a spatial point for each homestead from imagery and the subsequent verification and capture of listing and address variables for each of the captured spatial points.

  • Enumeration Area (EA) demarcation: Natural and man made features such as riverbeds, watersheds, roads and built up areas as visible on imagery are used to demarcate the boundaries of EAs. Imagery is also used to identify development in remote / rural areas where no other official sources such as cadastre exists to indicate development and habitation.

  • Map production: The most recent imagery applicable to specific an EA is used as backdrop in conjunction with vector data to create a map for purposes of listing, surveys and enumeration. The map production process is automated to the extent where the most recent image applicable to an EA is implemented.

  • Planning: Imagery is invaluable in identifying and reacting to cases where urban densification and development has occurred over a short time span. This is especially critical during censuses and surveys where logistical and human resources aspects of the projects need to be adapted and implemented to cater for such rapid change.

  • Master sample updates: Listing is a process where every dwelling is captured in terms of a detail description of the said dwelling. The latest version of imagery applicable to each primary sampling unit is used in support of this annual process.

Imagery sourcing initiatives:

  • Statistics South Africa does not have the capability of acquiring imagery directly itself. Where possible, it seeks partnerships to share the cost of acquisition of the imagery. 

  • These include partnerships with the National Department of Agriculture (with respect to imagery from the Satellite Application Centre of the CSIR) and the Department of Land Affairs (DLA). The Metros regularly update their imagery holdings and share this with Stats SA.

    Department of Land Affairs - Chief Directorate Surveys and Mapping (CDSM)

    • Statistics South Africa is currently collaborating with the CDSM to fast track the ortho rectification of the imagery acquired by the CDSM during the 2004 and 2005 flying seasons. 
    • Furthermore to this an additional 26 flight jobs have been earmarked for the 2006 flying season. These flight jobs – mostly in the North West province and Mpumalanga are currently being acquired and will be funded by Statistics South Africa.

    Council for Scientific and Industrial Research (CSIR) – Satellite Application Centre (SAC):

    • Statistics South Africa and the Department of Agriculture collaborated in acquiring 45 % of the coverage of South Africa with Spot 5 ( 2,5 m  resolution) imagery. The CSIR - SAC facilitated the project, which has currently expanded to include the remainder of South Africa and the addition of additional users contributing financially to this project.

    Dwelling frame:

    • The dwelling frame project (See Dwelling frame on home page) has contributed to the coverage of an additional 12 Municipalities with high resolution imagery over the 2005 / 6 period.

    Local Government:

    • Statistics South Africa has working relations with all six Metropolitan Municipalities who update their imagery coverage every second year on average. Other local municipalities are not as frequent in updating their imagery coverage, but are alos engaged in updating the Statistics South Africa database.
Map 1: shows the geographical extent of imagery from a variety of sources currently in the Geography division’s geo-database.  Where there are several vintages of photography, the more recent is superimposed on the older vintage.
 
Map 2: shows the geographical extent of imagery the Geography Division aspires to implement on the GIS within the current financial year.