{
  "@context": {
    "schema": "http://schema.org/",
    "dcterms": "http://purl.org/dc/terms/",
    "dcat": "http://www.w3.org/ns/dcat#",
    "prov": "http://www.w3.org/ns/prov#",
    "spdx": "http://spdx.org/rdf/terms#",
    "csvw": "http://www.w3.org/ns/csvw#",
    "cdi": "http://ddialliance.org/Specification/DDI-CDI/1.0/RDF/",
    "ex": "https://example.org/",
    "cdif": "https://cdif.org/0.1/"
  },
  "@id": "ex:gom-water-quality-long-2025",
  "@type": [
    "schema:Dataset"
  ],
  "schema:name": "Gulf of Maine water-quality monitoring stations, 2025 (long form)",
  "schema:description": "Same monthly water-quality observations from 12 buoys as the wide-form release, recast in long (narrow) form. Each row is one observation: station, date, parameter name (descriptor), value, and reporting unit.",
  "schema:identifier": {
    "@type": [
      "schema:PropertyValue"
    ],
    "schema:propertyID": "https://doi.org",
    "schema:value": "10.5281/zenodo.5151516",
    "schema:url": "https://doi.org/10.5281/zenodo.5151516"
  },
  "schema:version": "2025.10",
  "schema:dateModified": "2025-10-20",
  "schema:datePublished": "2025-10-20",
  "schema:license": [
    "https://creativecommons.org/licenses/by/4.0/"
  ],
  "schema:keywords": [
    "water quality",
    "Gulf of Maine",
    "long format",
    "tidy data"
  ],
  "schema:creator": {
    "@list": [
      {
        "@id": "https://ror.org/03m2x1q45",
        "@type": [
          "schema:Organization"
        ],
        "schema:name": "University of Arizona"
      }
    ]
  },
  "schema:publisher": {
    "@id": "https://ror.org/03m2x1q45",
    "@type": [
      "schema:Organization"
    ],
    "schema:name": "University of Arizona"
  },
  "prov:wasDerivedFrom": [
    {
      "@id": "ex:gom-water-quality-wide-2025",
      "schema:name": "Wide-form release of the same observations"
    }
  ],
  "schema:distribution": [
    {
      "@type": [
        "schema:DataDownload",
        "cdi:LongStructureDataSet",
        "cdi:PhysicalDataSet"
      ],
      "schema:name": "Long-form water-quality observations (CSV)",
      "schema:contentUrl": "https://example.org/data/gom-water-quality-long-2025.csv",
      "schema:encodingFormat": [
        "text/csv"
      ],
      "cdi:characterSet": "UTF-8",
      "cdif:fileSize": 712,
      "cdif:fileSizeUofM": "KB",
      "spdx:checksum": {
        "@type": [
          "spdx:Checksum"
        ],
        "spdx:algorithm": "SHA256",
        "spdx:checksumValue": "8b1a7c3e5d9f0a2b4c6d8e0f1a3b5c7d9e1f2a4b6c8d0e2f4a6b8c0d2e4f6a8b"
      },
      "cdi:isDelimited": true,
      "csvw:delimiter": ",",
      "csvw:header": true,
      "csvw:headerRowCount": 1,
      "csvw:quoteChar": "\"",
      "csvw:skipBlankRows": true,
      "countRows": 576,
      "countColumns": 5,
      "cdif:hasPhysicalMapping": [
        {
          "cdif:index": 0,
          "cdif:format": "string",
          "cdif:physicalDataType": "string",
          "cdi:isRequired": true,
          "cdif:formats_InstanceVariable": {
            "@id": "ex:var-station"
          }
        },
        {
          "cdif:index": 1,
          "cdif:format": "YYYY-MM-DD",
          "cdif:physicalDataType": "date",
          "cdi:isRequired": true,
          "cdif:formats_InstanceVariable": {
            "@id": "ex:var-sample-date"
          }
        },
        {
          "cdif:index": 2,
          "cdif:format": "string",
          "cdif:physicalDataType": "string",
          "cdi:isRequired": true,
          "cdif:formats_InstanceVariable": {
            "@id": "ex:var-parameter"
          }
        },
        {
          "cdif:index": 3,
          "cdif:format": "decimal",
          "cdif:physicalDataType": "float64",
          "cdi:nullSequence": "NA",
          "cdi:isRequired": true,
          "cdif:formats_InstanceVariable": {
            "@id": "ex:var-value"
          }
        },
        {
          "cdif:index": 4,
          "cdif:format": "string",
          "cdif:physicalDataType": "string",
          "cdif:formats_InstanceVariable": {
            "@id": "ex:var-unit"
          }
        }
      ]
    }
  ],
  "schema:variableMeasured": [
    {
      "@id": "ex:var-station",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "station_id",
      "schema:description": "Monitoring station identifier; unit of observation.",
      "cdif:physicalDataType": "string",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#string",
      "cdif:role": "UnitIdentifier",
      "cdif:displayLabel": [
        "Monitoring station"
      ]
    },
    {
      "@id": "ex:var-sample-date",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "sample_date",
      "schema:description": "Date the water sample was collected.",
      "cdif:physicalDataType": "date",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#date",
      "cdif:role": "Dimension",
      "cdif:displayLabel": [
        "Sampling date"
      ]
    },
    {
      "@id": "ex:var-parameter",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "parameter",
      "schema:description": "Descriptor column. Each value names the measured property whose numeric reading is recorded in the value column. Permitted codes are ph, temperature, salinity, dissolved_oxygen.",
      "cdif:physicalDataType": "string",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#string",
      "cdif:role": "Descriptor",
      "cdif:displayLabel": [
        "Parameter"
      ]
    },
    {
      "@id": "ex:var-value",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "value",
      "schema:description": "Reference column. Holds the numeric value of whichever parameter is named in the descriptor column for that row.",
      "cdif:physicalDataType": "float64",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#decimal",
      "cdif:role": "ReferenceVariable",
      "cdif:displayLabel": [
        "Measured value"
      ]
    },
    {
      "@id": "ex:var-unit",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "unit",
      "schema:description": "Reporting unit symbol for the row's value (e.g., Cel, 1, mg/L).",
      "cdif:physicalDataType": "string",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#string",
      "cdif:role": "Attribute",
      "cdif:displayLabel": [
        "Unit of measure"
      ],
      "cdi:qualifies": {
        "@id": "ex:var-value"
      }
    },
    {
      "@id": "ex:var-ph",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "ph",
      "schema:description": "pH parameter. Rows whose descriptor column equals 'ph' record values for this variable.",
      "schema:measurementTechnique": "Glass electrode, two-point calibration",
      "cdif:physicalDataType": "float64",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#decimal",
      "cdif:role": "Measure",
      "schema:minValue": 0.0,
      "schema:maxValue": 14.0,
      "cdif:displayLabel": [
        "pH"
      ],
      "cdif:simpleUnitOfMeasure": "1",
      "cdif:uses": [
        {
          "@id": "http://vocab.nerc.ac.uk/collection/P01/current/PHXXZZXX/"
        }
      ]
    },
    {
      "@id": "ex:var-temperature",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "temperature",
      "schema:description": "Temperature parameter. Rows whose descriptor column equals 'temperature' record values for this variable.",
      "schema:measurementTechnique": "CTD profiler",
      "cdif:physicalDataType": "float64",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#decimal",
      "cdif:role": "Measure",
      "schema:minValue": -2.0,
      "schema:maxValue": 30.0,
      "cdif:displayLabel": [
        "Sea-water temperature"
      ],
      "cdi:describedUnitOfMeasure": {
        "@type": [
          "schema:DefinedTerm"
        ],
        "schema:name": "degree Celsius",
        "schema:identifier": "http://qudt.org/vocab/unit/DEG_C"
      },
      "cdif:simpleUnitOfMeasure": "Cel"
    },
    {
      "@id": "ex:var-salinity",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "salinity",
      "schema:description": "Practical salinity parameter. Rows whose descriptor column equals 'salinity' record values for this variable.",
      "schema:measurementTechnique": "CTD profiler",
      "cdif:physicalDataType": "float64",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#decimal",
      "cdif:role": "Measure",
      "schema:minValue": 0.0,
      "schema:maxValue": 42.0,
      "cdif:displayLabel": [
        "Practical salinity"
      ],
      "cdif:simpleUnitOfMeasure": "1",
      "cdif:uses": [
        {
          "@id": "http://vocab.nerc.ac.uk/collection/P01/current/PSALST01/"
        }
      ]
    },
    {
      "@id": "ex:var-dissolved-oxygen",
      "@type": [
        "schema:PropertyValue",
        "cdi:InstanceVariable"
      ],
      "schema:name": "dissolved_oxygen",
      "schema:description": "Dissolved oxygen parameter. Rows whose descriptor column equals 'dissolved_oxygen' record values for this variable.",
      "schema:measurementTechnique": "Optode sensor",
      "cdif:physicalDataType": "float64",
      "cdi:intendedDataType": "https://www.w3.org/TR/xmlschema-2/#decimal",
      "cdif:role": "Measure",
      "schema:minValue": 0.0,
      "schema:maxValue": 15.0,
      "cdif:displayLabel": [
        "Dissolved oxygen"
      ],
      "cdi:describedUnitOfMeasure": {
        "@type": [
          "schema:DefinedTerm"
        ],
        "schema:name": "milligram per litre",
        "schema:identifier": "http://qudt.org/vocab/unit/MilliGM-PER-L"
      },
      "cdif:simpleUnitOfMeasure": "mg/L"
    }
  ],
  "schema:measurementTechnique": [
    "CTD profiler",
    "Glass electrode pH meter",
    "Optode dissolved-oxygen sensor"
  ],
  "schema:spatialCoverage": [
    {
      "@type": [
        "schema:Place"
      ],
      "schema:name": "Gulf of Maine",
      "schema:geo": {
        "@type": [
          "schema:GeoShape"
        ],
        "schema:box": "41.0 -71.0 45.0 -65.0"
      }
    }
  ],
  "schema:temporalCoverage": [
    "2025-01-01/2025-12-31"
  ],
  "schema:subjectOf": {
    "@id": "ex:gom-water-quality-long-2025/catalog-record",
    "@type": [
      "schema:Dataset"
    ],
    "schema:additionalType": [
      "dcat:CatalogRecord"
    ],
    "schema:about": {
      "@id": "ex:gom-water-quality-long-2025"
    },
    "schema:sdDatePublished": "2025-10-20",
    "dcterms:conformsTo": [
      {
        "@id": "https://w3id.org/cdif/core/1.1"
      },
      {
        "@id": "https://w3id.org/cdif/discovery/1.1"
      },
      {
        "@id": "https://w3id.org/cdif/data_description/1.1"
      }
    ]
  }
}