Urban road network detection from satellite imagery

The second generation of satellites such as Landsat TM (30 meter resolution), SPOT (10 and 20 meter resolution) and the third generation of high-resolution satellites such as Quickbird and IKONOS (1 and 4 meter resolution) have gradually reduced dependency on classical methods of updating transportation networks (field survey, aerial photography). A combination of Landsat TM, SPOT, HRV, and IKONOS imageries were used to classify land use digitally and update transportation network in Al Ain, UAE using on-screen digitisation. The technique of on-screen digitisation, for updating road network from satellite imageries, had been adopted by various researchers and organisations, for example, the US Bureau of the Census. The advantage of updating transportation network using on-screen digitisation is that data will ready for integration with other layers in a GIS environment. All these layers can be linked to transportation planning models for further processing and analysis.