Disaster Risk Assessment and Geographic Information Systems/Science (GISc)

Disaster Risk Assessment and Geographic Information Systems/Science (GISc)

Disaster risk assessment is a spatial study or assessment of disaster risk of a specific area that can include all three levels of government (local, district, provincial).  The statement is a logical one because hazards occur at a specific location and its impact on people and environment is also based on where.  This makes GIS an ideal tool to do Disaster Risk Assessment.


GIS can be many things, it can be a software tool, a system and/or a science (Geographical Information Science).  All three work together to deliver a GIS product which can be many things.  A map depicting the water network of a city, a model simulating water flow in the water network and the hardware and software necessary to produce the previously mentioned products.

Five elements (Figure 1) of a GIS (system) includes the hardware, software, procedures and processes, data and most important the people.


Figure 1:  Five elements of a GIS

GIS as a spatial science has its foundation in Geography, Information Science, Mathematics, Physics, Photogrammetry and a few more. 

GIS is applied in many disciplines that range from environmental studies, engineering, municipal services, disaster management, business intelligence, navigation, etc.  Important to remember is that although GIS is applied in these fields, the foundation is still in the science.

Disaster risk assessment

The South African National Disaster Management Framework indicates that Disaster Risk Assessment is a process that determines the level of risk by:

  • Identifying and analysing potential hazards and/or threats.
  • Assessing the conditions of vulnerability that increase the chance of loss for particular elements-at-risk (that is, environmental, human, infrastructural, agricultural, economic and other elements that are exposed to a hazard, and are at risk of loss).
  • Determining the level of risk for different situations and conditions.
  • Helping to set priorities for action.

A scientific approach, combining indigenous knowledge; historical data; hazard, vulnerability and risk indicators, is used to assess disaster risk as prescribed by the mentioned framework.

Disaster Risk Assessment and GIS

As mentioned earlier, hazards and disaster risk are spatial phenomena and a GIS is the ideal of not only tool that must be used to do the assessments.  Various GIS techniques exist that can be used in the assessment process.  These techniques include amongst other things:

  • Spatial query and selection (identification of land use subjected to flooding).
  • Buffering (distance from factory manufacturing paint).
  • Cluster creation (identification of high-risk areas).
  • Hotspot analysis (identification of high-risk areas).
  • Pattern analysis (identification of future risk areas).
  • Modeling of spatial relationships (identification of future risk areas).

GIS software is used to visualise the results from the assessments by creating maps and 3d models.  The results can also be stored in a corporate GIS (which can be online) that can be viewed from everywhere for management and/or disaster management officials.

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