The Aerial Photography Field Office is a division of the Farm Service Agency (FSA), of the United States Department of Agriculture (USDA). The USDA has been involved in the acquisition, use and distribution of aerial photography for more than 65 years. The Farm Service Agency has used aerial photography to track farm records by drafting farm tract and field boundaries onto aerial photographic enlargements. This allowed for USDA workers and farmers to interact with USDA farm programs. The aerial photos were rectified to allow for accurate measurements and counties were furnished new imagery on average every five years. Different imagery programs, such as the National Aerial Photography Program (NAPP) and the National Digital Orthophoto Program (NDOP) were created to take a greater acquisition of the farm lands on a national scale and provide consistent coverage. Aerial photography and digital orthophotography acquired by the USDA are in the public domain and are available to federal and state agencies, and to the general public through the Aerial Photography Field Office.