Experiment on the Impact of Spatial Resolution on Building Extraction Accuracy

Natural Resources Canada is in the process of defining spatial resolution requirements for a national scale optical imagery service. This study aims to evaluate the impact of spatial resolution on residential buildings extraction accuracy in an urban context. The hypothesis is that as spatial resolution gets coarser, there will be a decrease in successful identification. A 3-band Worldview-3 image was used for a study site located in Toronto, Canada. Buildings were manually extracted independently by specialized technicians for five different resolutions ranging from 30 cm to 2.5 m. Results show similar extraction accuracy between 0.3 m and 0.7 m (>90%). There is a significant decrease in accuracy for resolutions of 1 m and coarser. The study demonstrates that a spatial resolution of 0.7 m or better is required for accurate building extraction in an urban context.