Remote sensing-based fire frequency mapping in a savannah rangeland

Abstract

Burnt area mapping and fire frequency analysis were carried out in Hwange National Park, Zimbabwe. Hwange National Park typifies a savannah ecosystem which is semi-arid and fire-prone. This paper presents a geospatial analysis to quantify the spatial distribution and fire frequency from 2000 to 2006. Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2000 to 2006 were obtained and classified for burnt area mapping. Linear pixel unmixing was used for image classification and subsequent mapping of burnt areas. The results showed that it was feasible to have discrimination of burnt areas and ‘un-burnt’ areas as well as generating a six year fire frequency map of the study area. Accuracy assessment of the classified images was carried out using field obtained information on fire occurrence to validate the classification results. An error matrix quantified accuracy of classified maps through producer's accuracy, user's accuracy and overall accuracy. High overall accuracy rates of appromately 96%, in turne, justify use of linear pixel unmixing in identifying and mapping burnt areas. Thus pixel unmixing offers a viable mapping tool for fire monitoring and management in protected areas.