{
    "tag": 18223,
    "title": "Orthomosaic images from UAS surveys of the upper reservoir delta at Jenkinson Lake, El Dorado County, California",
    "pubdate": "20240807",
    "sername": null,
    "series_name": null,
    "issue": "DOI:10.5066\/P14QWDYN",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/pcmsc\/DataReleases\/ScienceBase\/DR_P14QWDYN\/JenkinsonLake_orthomosaic_metadata.faq.html",
    "format": null,
    "email": null,
    "descript": "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.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "Logan, Joshua B.",
            "role": "Author"
        },
        {
            "name": "East, Amy E.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "15",
            "name": "aerial photography",
            "scope": "The process of taking pictures with a camera from an aircraft. Use for both the process of photography from the air and the images produced by the process."
        },
        {
            "thcode": 2,
            "code": "384",
            "name": "fires",
            "scope": "Combustion, marked by flames or intense heat, in natural settings, often ignited by lightning or human activities.  For fires set as part of natural resource management, use 'controlled fires'."
        },
        {
            "thcode": 2,
            "code": "468",
            "name": "geomorphology",
            "scope": "Branch of geology dealing with surface land features and the processes that create and change them."
        },
        {
            "thcode": 2,
            "code": "474",
            "name": "geospatial datasets",
            "scope": "Collections of related digital information that are geographically referenced."
        },
        {
            "thcode": 2,
            "code": "2046",
            "name": "image mosaics",
            "scope": "Composite images formed by overlapping existing images, typically arranged to achieve greater spatial coverage."
        },
        {
            "thcode": 2,
            "code": "981",
            "name": "remote sensing",
            "scope": "Acquiring information about a natural feature or phenomenon, such as the Earth's surface, without actually being in contact with it. USGS remote sensing is usually carried out with airborne or spaceborne sensors or cameras."
        },
        {
            "thcode": 2,
            "code": "1749",
            "name": "topographic maps",
            "scope": "Maps depicting the elevation and relief of the land surface or depth of a water body (bathymetry) in an area, usually shown using contour lines.  Typically these maps include manmade features and administrative boundaries as well as vegetation and hydrographic features."
        },
        {
            "thcode": 2,
            "code": "1176",
            "name": "topography",
            "scope": "Configuration of the land surface and sea floor."
        },
        {
            "thcode": 15,
            "code": "006",
            "name": "elevation",
            "scope": "Height above or below sea level, for example altitude, bathymetry, digital elevation models, slope, derived products, DEMs, TINs"
        },
        {
            "thcode": 15,
            "code": "008",
            "name": "geoscientificInformation",
            "scope": "Information pertaining to earth sciences, for example geophysical features and processes, geology, minerals, sciences dealing with the composition, structure and origin of the earth's rocks, risks of earthquakes, volcanic activity, landslides, gravity information, soils, permafrost, hydrogeology, groundwater, erosion"
        },
        {
            "thcode": 23,
            "code": "22",
            "name": "Bathymetry and Elevation",
            "scope": "Includes measures of the height of a location above or below a reference surface. Bathymetry is the elevation of the Earth's surface beneath a body of water, especially the ocean, typically determined by measurements of depth from the water surface at mean lower low water. Distributions are topographic maps and bathymetric charts based on collected data and also include smoothed or gridded maps of bathymetry and elevation from observational data or other associated factors. Assessment data types include models of ecological value, economic value, or current rates of alterations due to erosion, accretion, climate change, and other stressors (for example, wetland habitat loss). Predictions are the results of models or projections of future distributions, values, or ecological impacts of bathymetry, including predicted changes due to natural and human forces such as erosion, deposition, sea-level rise, and dredging activities; predictions also include the results of scenario-based models of bathymetry changes under different management strategies."
        },
        {
            "thcode": 61,
            "code": "450",
            "name": "aerial and satellite photography",
            "scope": "used for vertical or oblique photography of the Earth taken from aircraft or satellites; do not use for air-to-air photography."
        },
        {
            "thcode": 61,
            "code": "447",
            "name": "altimetry",
            "scope": "used for all instruments and techniques that determine altitude, either directly or remotely, including (but not limited to) pressure altimeters, radar altimeters, GPS, and LIDAR."
        },
        {
            "thcode": 61,
            "code": "452",
            "name": "orthophotography",
            "scope": "aerial photography corrected for distortion (\"orthorectified\") to create an image with uniform scale."
        },
        {
            "thcode": 61,
            "code": "445",
            "name": "photography",
            "scope": "limited to photography for scientific purposes."
        },
        {
            "thcode": 61,
            "code": "449",
            "name": "remote sensing",
            "scope": "generally used for the acquisition of images or other data from aircraft or satellites; also used for ground-based systems for collecting data at a distance."
        }
    ],
    "place_term": [],
    "image": [
        {
            "name": "https:\/\/www.sciencebase.gov\/catalog\/file\/get\/667c598cd34e828a20a696d8?name=JenkinsonLake_2021-11-04_orthomosaic_browse.jpg&allowOpen=True",
            "description": "Orthomosaic image from 2021-11-04 UAS survey."
        }
    ],
    "fan": [
        "2021-655-FA",
        "2021-659-FA",
        "2022-666-FA",
        "2023-678-FA"
    ]
}