Towards a methodology for the use of geo-information technology in disaster assessment

Data associated with disasters is inherently spatial, and geo-information technology (G-IT) has been shown to be central to the integration, analysis, visualization, knowledge generation and communication during an event (Ahearn et al, 2006). Whereas geoinformation technology is readily available, it still appears to be underutilised, especially in the case of events occurring in a small geographical area, or events with a lesser impact (Smith, 2001).


Introduction
Disaster assessment entails the description of disaster events and their impact on human lives, property and the environment.Information is a vital component of this process, and geo-information technology in particular should have a key role in this regard.
Data associated with disasters is inherently spatial, and geo-information technology (G-IT) has been shown to be central to the integration, analysis, visualization, knowledge generation and communication during an event (Ahearn et al, 2006).
Whereas geo-information technology is readily available, it still appears to be underutilised, especially in the case of events occurring in a small geographical area, or events with a lesser impact (Smith, 2001).Ahearn et al, (2006), Guha-Sapir & Below (2006), and Smith, (2001) mention a number of factors contributing to the lack of G-IT application.These can be grouped into two categories: institutional problems and technical problems.

Institutional problems include the following:
• The capturing of data on disaster occurrence is not institutionalised; • There is a lack of standardised data collection methodologies; • The pressure to respond quickly for fund raising or relief planning is usually paramount; • Prevention planning and community preparedness programmes are rarely funded; • The costs of hazard mapping and detailed inventories are perceived to be high.

Technical problems include:
• lack of suitable software in place; • lack of human resources dedicated to G-IT functions; • lack of suitable training; • lack of understanding of the technology by responders (DRM officials); • a disconnect between the producers of geospatial data and the consumers of it; • the existence of data gaps, scale inconsistencies, and data currency; • Lack of meta-data.
The lack of available data in respect of disasters is singled out as a major weakness for long-term planning (Guha-Sapir & Below, 2006).To address this, a methodology for the sustainable application of G-IT in disaster assessment should be developed.
An opportunity to establish a research project for this purpose was identified shortly after the floods that occurred in the Southern Cape in July 2006. .

The Research Project
The research project, registered with the African Centre for Disaster Studies (ACDS) at North-West University in South Africa (Potchefstroom Campus), is based on a desktop study of relevant literature, a practical exercise and an analysis of information.This paper focuses on the practical component of GIS activities to demonstrate the value of a GIS-based methodology.

Problem Statement
As indicated above, there is a lack of well structured geo-referenced data on disaster events.The most comprehensive weather related hazard dataset to date, which is publicly available in South Africa, has been developed by the South African Weather Service.This is generally referred to as the 'Caelum' database (Poolman, 2006).
This database comprises a list of notable weather events in South Africa from 1961 and is updated regularly.
Although this database is comprehensive in terms of national scale, it falls short of local differentiation, as is illustrated in Figure 1.The events in the Caelum database are linked to place names, each represented by the same latitude & longitude coordinate for the same place.All the events in George, for example, will therefore be linked to the same location (point) on the map.
As a result the differentiation between the type of hazard in George, as listed in Table 2, fails from a mapping point of view (refer to Figure 1 and Nevertheless, the data can still be analysed, and useful information produced, as illustrated in Table 2.This information should be valuable in the prioritisation of risks, and as the database is updated with more events as they occur, it will remain current and useful for continuous analysis.

GEORGE FLOODS 5 GEORGE WIND 4 GEORGE SNOW 4
GEORGE HAIL 2

Towards a GIS-based methodology
According to Smith (2001: 119) one of the main practical limitations to long-term planning is the lack of knowledge about location, recurrence interval and hazard potential of events which might affect small parts of urban areas.The recurrence interval of hazards can only be measured if the data describing the events have been captured in a structured database.The value of this data will be improved if the geospatial extent of events has been captured as GIS data.The development of a practical methodology for disaster assessment is based on this viewpoint.
A GIS project was created to test a methodology focused on data sourcing, data integration, data processing and data analysis for a specific study area.The study area was Glentana, a coastal town in the Southern Cape, which was severely affected by floods during July 2006.The project was conducted in five phases, and is briefly described as follows: It was also required to capture land use data to establish the status quo of the

Conclusion
It has been proven that in the absence of the data required for an analytical disaster assessment, a GIS project could be established within a relative short period of time, focussing on the affected area.The project made use of existing data and new data sets were created that could be used not only for mapping purposes, but to retrieve statistics related to impacts.
The value of the data is further illustrated by the fact that it can be used in the future for various purposes, including disaster risk assessment, land use planning and environmental management.The challenge is to test and validate this methodology and to promote it within the DRM fraternity.

Figure 1 :
Figure 1: Map indicating the location of hazardous impact events in the Southern Cape.Source: Caelum database, 2005.Latitude/Longitude values captured as point data in PlanetGIS.

Figure 2 :
Figure 2: Example of topographical data in raster format.Source: Dept. of Land Affairs.Directorate Surveys & Mapping