Tile Index - This data set consists of 0.3-meter pixel resolution (approximately 1-foot), natural color orthoimages covering the Pittsburgh, PA Urban Area (Allegheny and Beaver Counties. 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. The design accuracy is estimated not to exceed 3-meter diagonal RMSE (2.12m RMSE in X or Y).