Estimating urban greenness index using remote sensing data: A case study of an affluent vs poor suburbs in the city of Johannesburg

Abstract

The importance of urban green space has over the years grown into an indispensable component of green infrastructure incorporated in urban planning and design as investment to promote the well-being of city dwellers. The continuous advancement in remote sensing spatial and spectral resolutions has made it possible to effectively map and evaluate urban green space for better management. The urban greenness index between the affluent suburb of Rosebank in the north and the poor Township of Soweto in the south, of Johannesburg city was assessed and compared to determine the environmental quality between the two areas. The total above ground biomass (AGB) of the two predominantly occurring street trees, Jacaranda mimosifolia and Platanus x acerifolia in Rosebank was estimated using existing allometric equations for the respective species. An equation was derived from the correlation of normalized difference vegetation index (NDVI) values extracted from SPOT 6 image and AGB of Rosebank. The same equation was then used to extrapolate and estimate the AGB of Soweto. The results showed that Rosebank had the lowest total AGB of approximately 113,179 ton, while that of Soweto was approximately 504,400 ton. However, the greenness index of Rosebank (83%) was greater than in Soweto (14%), indicating a pattern of ecological disparity between the two areas. These findings could be useful for designing a sound urban planning and policy formulation for the city of Johannesburg.

Keywords

• Urban greenness index
• Above ground biomass
• SPOT 6
• Platanus x acerifolia, Jacaranda mimosifolia