The United States Federal Emergency Management Agency (FEMA) is assessing technical methodologies and procedures for the collection, analysis, and computation of coastal erosion rates. It is likely that the methodology selected will involve the use of historical shoreline data compared with current shoreline information. This paper largely addresses the sources of errors inherent in the raw data. Source data include historical and recent National Ocean Service (NOS) T-sheets (produced ca. 1840s to present) and air photos (taken ca. late 1930s to present) as well as any other types of accurate map and photographic data. -from Authors
