1. Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Johannesburg, South Africa
2. Agricultural Research Council-Institute for Soil, Climate and Water (ARC-ISCW), Geoinformation Science Division, Pretoria, South Africa
3. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
4. School of Geography, Archaeological and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa