Combining Google Earth historical imagery and UAV photogrammetry for urban development analysis

Rural -urban migration often triggers additional demand for housing and infrastructural development to cater for the growing population in urban areas. Consequently, town planners and urban development authorities need to understand the urban development trend to make sustainable urban planning decisions. Yet, methods to analyse changes and trends in urban spatial development are often complex and require costly data collection. This article thus presents a simplified method to analyse the urban development trend in an area. The method integrates Google Earth (GE) historical imagery (baseline data) and unmanned aerial vehicle (UAV) photogrammetry (recent data) to quantify the changes over time. This approach can be applied to study the urban development trends in low-income countries with budget constraints. The method is discussed under four main headings: (1) background, (2) method details, (3) limitations, and (4) conclusion. center dot Google Earth historical image can be extracted with its associated world file. center dot The population of an area can be estimated by using average household size data and the number of residential buildings in the area. center dot The building height ratio can be used to ascertain if the land is being used parsimoniously.