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 2019-11-12. 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 image was acquired from a manned aircraft on 2019-11-12. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Hasselblad A6D-100c camera. The imagery was acquired from an approximate altitude of 880 meters (2,900 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.

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 2018-12-02. 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 image was acquired from a manned aircraft on 2018-12-02. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Nikon D850 camera. 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 single-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.

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 2018-12-02. 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 image was acquired from a manned aircraft on 2018-12-02. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Nikon D850 camera. 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 single-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.

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 2020-11-10. The orthomosaic is available in a high-resolution 5-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 image was acquired from a manned aircraft on 2020-11-10. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Hasselblad A6D-100c camera. The imagery was acquired from an approximate altitude of 880 meters (2,900 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.

This portion of the data release presents an RGB orthomosaic image of an expanded area surrounding Whiskeytown Lake derived from Structure from Motion (SfM) processing of aerial imagery acquired on 2019-06-03. The orthomosaic is available in a high-resolution 14-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 image 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 expanded AOI for this dataset (referred to as AOI-B) covered an area around Whiskeytown Lake up to the adjacent ridgelines. The goal for expanding the AOI for this acquisition was to create an orthomosaic image to qualitatively assess the post-fire erosion patterns in upslope areas of the drainages. The imagery for this AOI was acquired from an approximate altitude of 1,160 meters (3,800 feet) above ground level, to produce a nominal ground sample distance (pixel size) of 10 centimeters (4 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.

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.

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.

This portion of the data release presents high-resolution orthomosaic images of the Jenkinson Lake upper reservoir delta in El Dorado County, California. The orthomosaics have resolutions of 2.5 centimeters per pixel and were derived from structure-from-motion (SfM) processing of aerial imagery collected during surveys with unoccupied aerial systems (UAS). The surveys were on 2021-10-13, 2021-11-04, 2022-10-25, and 2023-11-13, and were generally timed to coincide with low water level in the reservoir to maximize sub-aerial coverage. The raw imagery used to create the orthomosaics was acquired with a UAS quadcopter fitted with a Ricoh GR II digital camera featuring a global shutter. The UAS was flown on pre-programmed autonomous flight lines spaced to provide approximately 70 percent overlap between images from adjacent lines, from an approximate altitude of 100 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. The raw imagery was geotagged using positions from the UAS onboard single-frequency autonomous GPS. Survey control was established using temporary ground control points (GCPs) consisting of a combination of small square tarps with black-and-white cross patterns and temporary chalk marks placed on the ground. The GCP positions were measured using dual-frequency real-time kinematic (RTK) GPS with corrections referenced to a static base station operating nearby. The images and GCP positions were used for structure-from-motion (SfM) processing to create topographic point clouds, high-resolution orthomosaic images, and DSMs. The orthomosaic images are provided in a three-band RGB format, with 8-bit unsigned integer values compressed using high-quality JPEG compression, and are formatted as cloud optimized GeoTIFFs with internal overviews and masks to facilitate cloud-based queries and display.

This portion of the data release presents high-resolution orthomosaic images of the Jenkinson Lake upper reservoir delta in El Dorado County, California. The orthomosaics have resolutions of 2.5 centimeters per pixel and were derived from structure-from-motion (SfM) processing of aerial imagery collected during surveys with unoccupied aerial systems (UAS). The surveys were on 2021-10-13, 2021-11-04, 2022-10-25, and 2023-11-13, and were generally timed to coincide with low water level in the reservoir to maximize sub-aerial coverage. The raw imagery used to create the orthomosaics was acquired with a UAS quadcopter fitted with a Ricoh GR II digital camera featuring a global shutter. The UAS was flown on pre-programmed autonomous flight lines spaced to provide approximately 70 percent overlap between images from adjacent lines, from an approximate altitude of 100 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. The raw imagery was geotagged using positions from the UAS onboard single-frequency autonomous GPS. Survey control was established using temporary ground control points (GCPs) consisting of a combination of small square tarps with black-and-white cross patterns and temporary chalk marks placed on the ground. The GCP positions were measured using dual-frequency real-time kinematic (RTK) GPS with corrections referenced to a static base station operating nearby. The images and GCP positions were used for structure-from-motion (SfM) processing to create topographic point clouds, high-resolution orthomosaic images, and DSMs. The orthomosaic images are provided in a three-band RGB format, with 8-bit unsigned integer values compressed using high-quality JPEG compression, and are formatted as cloud optimized GeoTIFFs with internal overviews and masks to facilitate cloud-based queries and display.

This portion of the data release presents a high-resolution orthomosaic image of the exposed Los Padres Reservoir delta where the Carmel River enters the reservoir. The orthomosaic has a resolution of 2.5 centimeters per pixel and was derived from structure-from-motion (SfM) processing of aerial imagery collected with an unoccupied aerial system (UAS) on 2017-11-01. The raw imagery used to create the orthomosaic was acquired using a UAS fitted with a Ricoh GR II digital camera featuring a global shutter. The UAS was flown on pre-programmed autonomous flight lines spaced to provide approximately 70 percent overlap between images from adjacent lines. The camera was triggered at 1 Hz using a built-in intervalometer. The UAS was flown at an approximate altitude of 100 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. The raw imagery was geotagged using positions from the UAS onboard single-frequency autonomous GPS. Twenty temporary ground control points (GCPs) consisting of small square tarps with black-and-white cross patterns were distributed throughout the area to establish survey control. The GCP positions were measured using real-time kinematic (RTK) GPS, using corrections from a GPS base station located on a benchmark designated SFML, located approximately 1 kilometer from the study area. The orthomosaic image is provided in a three-band RGB format, with 8-bit unsigned integer values compressed using high-quality JPEG compression. The image has been formatted as a cloud optimized GeoTIFF with internal overviews and masks to facilitate cloud-based queries and display.