Visualisation technical Veld fire rapid impact assessment by Dawie Jansen van Vuuren, MetroGIS and Dewald van Niekerk, North-West University

Each year in , thousands of hectares of agricultural land, livestock, farming equipment, houses and lives are lost due to raging veld fires. During August 2011 the North-West Province experienced significant veld fires and on 23 August 2011, intense veld fires ravaged the areas around Fochville, , Carletonville, Boskop, Amalia and .

t one time 13 veld fires were burning, which quickly depleted Athe response capabilities of the role-players. The damage caused and losses sustained quickly exceeded the resources of the local authorities and affected communities. Initial assessments pointed to the possible declaration of a state of disaster as per the Disaster Management Act 57 of 2002.

To scientifically inform the declaration, a rapid impact assessment (RIA) of the extent of damages was undertaken by the African Centre for Disaster Studies (ACDS) at North West University in partnership with MetroGIS, for the Dr. Kenneth Kaunda District Municipality and the Tolkwe Local Municipality. Fig. 1: Enhanced false colour MODIS images of North West province, showing burn scars in dark red. The immediate need was to determine the spatial extent of burned areas, as well as the losses associated with the burned areas, normal GPS survey assist in determining and mapping fires. Spatial data was utilised as one of techniques are not practical. Remotely previous burns. To assist in this the assessment tools. sensed data was therefore a vital process, a fly-over in a helicopter was Spatial information technology plays a source of information. In this regard arranged with the assistance of the crucial role in various aspects of impact the Wide Area Monitoring Information South African Police Service. In this assessment as it functions in a multi- System (WAMIS) portal, developed instance GPS technology was used disciplinary environment. The primary and maintained by the CSIR Meraka to capture tracks as the helicopter functions of data collection, data Institute, provided an invaluable circled around those burned areas of service, making available a range of processing and data representation all concern. Previous burned areas were data and information products that played an important role in the RIA also captured for correlation with could be exploited to identify burned process. historical data. The data created from areas. This included MODIS satellite this process was later used to mask out The main objective of the RIA process imagery and textual data describing areas on the MODIS image for further was to answer the following key the location of active fires on a daily questions: basis (see Fig. 1). processing.

 Which geographical areas were The data obtained included all veld Processing affected? fires which have been occurring  What is the extent of these areas? The processing of data was aimed since the start of the winter season, at isolating identified burned areas  Which farms have been affected? many of those being controlled fires and extracting accurate GIS polygons to prepare fire breaks. To obtain an Input for those areas.This involved several accurate assessment the controlled steps of image processing and data For the purpose of declaring a state of fire data had to be identified for extraction, including the following: disaster the extent of damage needs exclusion. It was thus necessary to to be determined accurately. Due to ground truth the spatial data through  Undertaking an unsupervised the large geographical extent of the direct observation. This would also classification of the MODIS image

PositionIT – October 2011 49 VISUALISATION technical

fires, as this will over the years become an invaluable data source for ongoing research. The identified areas could then be overlaid with land parcel datasets which was used to provide a very accurate assessment of the burned areas per farm portion. This in turn could be triangulated with the self-assessment conducted by the various land owners.

Current research

During the course of the RIA a number of shortcomings and problems were identified. These range from the quality of data to the integration of Fig. 2: Unsupervised classification of MODIS image showing burned areas in red. technologies. In this regard the RIA research team together with a team of multi-disciplinary specialists, are now involved in ongoing research.

The objective of the current research is to examine the veld fire season of 2011 in all its facets linked to various disciplinary research questions. It will also assist in establishing a scientifically based and practical methodology to undertake rapid impact assessment within the broader context of disaster risk management in future. This project aims at answering key questions such as:

 What was the origin(s) of the fire hazard? Fig. 3: GIS polygons (red lines) created from extracted MODIS image data.  What were the initial and progressive characteristics of the fire hazard?  Which geographical areas were affected?  What direct and indirect losses were sustained?  What are the future loss estimations?  What is the environmental impact?  What is the status quo of GIS in rapid impact assessment?  What datasets need to be established and maintained?  What processes and technologies need to be developed to maintain the required datasets?

Conclusion

The rapid impact assessment process that was undertaken for the August Fig. 4: Farms portions extracted for one of the burned areas in Tlokwe 2011 veld fires in the Dr Kenneth Municipality. Kaunda District Municipality in North-West Province proved to be a success, illustrating the importance of  Isolating raster values representing number of maps answering queries and burn scars on the image confirming information received from remotely sensed data and geospatial information technology to acquire  Raster to vector data conversion field work. Whereas maps are normally crucial information in a short period of perceived to be the main purpose of time. Output GIS activity, the value of the datasets The output of the process is a number that were created in this process lies Contact Dawie Jansen van Vuuren, of new datasets, both raster and in the establishment and maintenance MetroGIS, Tel 012 349-2884, vector. These were used to generate a of historical data with regard to veld [email protected]

50 PositionIT – October 2011