{
    "tag": 15031,
    "title": "Bathymetry data from Floras Lake, Oregon, June 2018",
    "pubdate": "20230213",
    "sername": null,
    "series_name": null,
    "issue": "DOI:10.5066\/P9FQQ5JN",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/pcmsc\/DataReleases\/ScienceBase\/DR_P9FQQ5JN\/floras18_bathy_metadata.faq.html",
    "format": null,
    "email": null,
    "descript": "This portion of the USGS data release presents bathymetry data collected during surveys performed in Floras Lake, Oregon in June 2018 (USGS Field Activity Number 2018-636-FA). Floras Lake is a coastal lake in southern Oregon that is separated from the Pacific Ocean by sand dunes. It is not influenced by tides, although water levels fluctuate seasonally. Lake bed bathymetry data were collected using two personal watercraft (PWCs) equipped with single-beam sonar systems and global navigation satellite system (GNSS) receivers. The sonar systems consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9-degree beam angle. Depths from the lakebed to the echosounder were calculated using the digitized acoustic backscatter and sound velocity profiles, measured using a YSI CastAway CTD. Positioning of the survey vessels was determined at 10 Hz using Trimble R7 GNSS receivers. Output from the GNSS receivers and sonar systems were combined in real time on the PWC by a computer running HYPACK hydrographic survey software. Navigation information was displayed on a video monitor, allowing PWC operators to navigate along survey lines at speeds of 2 to 3 m\/s. Survey-grade positions of the PWCs were achieved with a single-base station and differential post-processing. Positioning data from the GNSS receivers were post-processed using Waypoint Grafnav to apply differential corrections from a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12a offsets. Bathymetric data were merged with post-processed positioning data, raw data were examined and soundings adjusted in areas with aquatic vegetation, and spurious soundings were removed using a custom Graphical User Interface (GUI) programmed with the computer program MATLAB. The average estimated vertical uncertainty of the bathymetric measurements is 5 cm based on manufacturer-reported accuracies of the survey equipment. However, the effect of aquatic vegetation on the vertical accuracy of the bathymetric measurements is unknown. The final point data from the PWCs are provided in a comma-separated text file and are projected in cartesian coordinates using the Universal Transverse Mercator (UTM), Zone 10 North, meters coordinate system.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "La Selle, SeanPaul M.",
            "role": "Author"
        },
        {
            "name": "Stevens, Andrew W.",
            "role": "Author"
        },
        {
            "name": "Nasr, Brandon M.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "80",
            "name": "bathymetry",
            "scope": "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."
        },
        {
            "thcode": 2,
            "code": "82",
            "name": "bathymetry measurement",
            "scope": "Means of determining the depth to the floor of a body of water, especially the ocean."
        },
        {
            "thcode": 2,
            "code": "492",
            "name": "GPS measurement",
            "scope": "Determination of distance and location using instruments receiving signals from the Global Positioning System, a system of satellites for identifying earth locations."
        },
        {
            "thcode": 2,
            "code": "2035",
            "name": "single-beam echo sounder",
            "scope": "Acoustic technique for determining seafloor or lakebed depth directly below the instrument platform."
        },
        {
            "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": "417",
            "name": "Global Positioning System (GPS) observations",
            "scope": "the use of satellite signals from the Global Positioning System to determine the precise location of a terrestrial receiver."
        }
    ],
    "place_term": [],
    "image": [],
    "fan": [
        "2018-636-FA"
    ]
}