knot, knot (unit)

{
    "$id": "https://schemas.optimade.org/defs/v1.2/units/si/1970/temporary/knot",
    "$schema": "https://schemas.optimade.org/meta/v1.2/optimade/physical_unit_definition.json",
    "title": "knot",
    "symbol": "knot",
    "display-symbol": "knot",
    "description": "A unit of speed primarily used in navigation defined as 1 nautical mile per hour which is equal to (1852/3600) m/s using the 1967 SI units.\n\nThe knot unit appears in the International System of Units (SI), 1st ed. (1970) defined as \"1 nautical mile per hour = (1852/3600) m/s.\"\n\n- The International System of Units (SI), 1st ed. (1970) categorizes the unit as \"Units in use temporarily with the International System.\"\n- The International System of Units (SI), 7th ed. (1998) changes the categorization to \"Other non-SI units currently accepted for use with the International System.\"\n- The International System of Units (SI), 8th ed. (2006) changes the categorization to \"Other non-SI units.\"\n- The knot is omitted in the International System of Units (SI), 9th Edition (2019).",
    "resources": [
        {
            "relation": "Definition in the International System of Units (SI), 1st Edition",
            "resource-id": "https://www.bipm.org/en/publications/si-brochure"
        },
        {
            "relation": "Wikipedia article describing the unit",
            "resource-id": "https://en.wikipedia.org/wiki/Knot_(unit)"
        }
    ],
    "defining-relation": {
        "base-units": [
            {
                "symbol": "m",
                "id": "https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre"
            },
            {
                "symbol": "s",
                "id": "https://schemas.optimade.org/defs/v1.2/units/si/1967/base/second"
            }
        ],
        "base-units-expression": "ms^-1",
        "scale": {
            "numerator": 1852,
            "denominator": 3600
        }
    },
    "x-optimade-definition": {
        "label": "knot_si_1970_temporary",
        "kind": "unit",
        "format": "1.2",
        "version": "1.2.0",
        "name": "knot"
    }
}