This portion of the data release presents an RGB orthomosaic image of Whiskeytown Lake and the surrounding area derived from Structure from Motion (SfM) processing of aerial imagery acquired on 2019-06-03. The orthomosaic is available in a high-resolution 6-centimeter (cm) version, as well as a medium-resolution 25 cm version. The high-resolution version is divided into two tiles (east and west) to reduce file download sizes. All imagery is provided in a three-band cloud-optimized GeoTIFF format, with 8-bit unsigned integer values compressed using high-quality JPEG compression. The raw imagery used to create the orthomosaic was acquired from a manned aircraft on 2019-06-03. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Nikon D850 camera. The acquisition covered two areas-of-interest (AOI) at different scales. The AOI for this dataset (referred to as AOI-A) covered the area immediately surrounding Whiskeytown Lake, which is the same area imaged in the 2018-12-02 acquisition (also available as a part of this data release). The imagery was acquired from an approximate altitude of 610 meters (2,000 feet) above ground level, to produce a nominal ground-sample distance (pixel size) of 5 centimeters (2 inches). An onboard dual-frequency GPS receiver was used to record the precise time and position of each image. Coordinates for ground control points consisting of photo-identifiable objects were measured independently using survey-grade post-processed kinematic (PPK) GPS.
Orthomosaic imagery for Whiskeytown Lake and surrounding area, 2019-06-03