Datasets of historical aerial photograph orthomosaics of Lassen Volcanic National Park, California (1941, 1952, 1966, 1973, 1998 and 2004)

This data release publishes datasets of historical aerial photograph orthomosaics covering areas within and surrounding Lassen Volcanic National Park, California. The historical imagery provides a high-resolution, spatially contiguous record of the park?s landscape across six dates ranging from 1941-2004. A total of 990 hard-copy aerial photographs taken in 1941, 1952, 1966, 1973, 1998, and 2004 were scanned at 800 dpi with an Epson Expression 12000XL. The 1941-1966 images are in black and white and scanned in 16-bit greyscale, and 1973, 1998 and 2004 are in color and scanned as 24-bit RGB. Like many historical aerial photograph collections, most of the flight and camera parameters were missing; Structure-from-Motion (SfM) software offers an efficient solution for orthorectifying images that lack these parameters. We used a SfM software called Agisoft Metashape Professional (v.1.6) to generate the orthomosaics for each image year, which were aligned with sets of reference Ground Control Points (GCPs). Average Root Mean Square Error (RMSE) ranged from 4.07-140 cm, and average reprojection errors ranged from 0.56-0.78 meters. Each orthomosaic metadata file contains specific information on image processing, number of GCPs used and estimated error.