"An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. For this dataset, black and white imagery was acquired in December, 2002 over the New Orleans - Metairie, LA Metropolitain area. Orthoimages were produced at1 foot (.3049 meter) pixel resolution. Each orthoimage provides coverage over approximately one quarter of a 7.5-minute quadrangle. Overlap is variable up to 1000 feet. The projected coordinate system is UTM zone 15 on the NAD83 datum. Imagery extending into UTM zone 16 is also projected into UTM zone 15. Individual files are named using the 7.5-minute USGS quadrangle name and associated quadrant."