{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Jenny L Hanson", "hasEmail": "mailto:jhanson@usgs.gov"}, "description": "These data are digital hillshades of the bathymetry for five (of six) sites where known rock structures exist in the St. Croix River. Hillshades are shaded relief surfaces created by the illumination source angle and shadows, and are being used to investigate the use of hydroacoustic technologies for quantifying habitat for imperiled mussels Spectaclecase (Margaritifera monodonta) and Salamander (Simpsonaias ambigua) typically associated with rock structures (e.g., wing dams, revetment) in rivers. Hillshades are essential for visualizing details of underwater terrain and it represents a shaded relief surface of the topography. Multibeam sonar data were collected using a Norbit integrated wide band multibeam system compact (iWBMSc) sonar unit. Hillshades are derived from bathymetry DEMs.  All hydroacoustic data were collected in early May of 2021, and the hillshades are provided in GeoTiff format.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9EUMCSF", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.63598bb7d34ebe442503eb3c.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_63598bb7d34ebe442503eb3c", "keyword": ["Minnesota", "Rock Outcrop", "Rock Substrate", "St. Croix River", "USGS-EMA-LOW-SB SMC: Freshwater mussels", "USGS:63598bb7d34ebe442503eb3c", "Wisconsin", "acoustic doppler current profiling", "bathymetry measurement", "benthic ecosystems", "endangered species", "image mosaics", "rivers", "sea-floor acoustic reflectivity", "sidescan sonar"], "modified": "2025-02-27T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-92.76360, 45.21650, -92.68450, 45.37120", "theme": ["geospatial"], "title": "700kHz Multibeam Bathymetry Hillshade of select Rock Outcrops of the St. Croix River, May 2021"}