Flooding is a leading cause of natural disaster in the United States. High-quality, digital mapping is essential to communicating flood hazard areas to those at risk. Urban expansion and land development have significantly altered the earth surface. New roads and flood drainage structures have an effect on projected floodwater depths, and land subsidence can be significant in coastal areas. As a result, flood disasters over the past years have created an increasing demand for precise, accurate and tangible data of the earth’s surface
