nmeasim::core::units¶

namespace nmeasim::core::units · Library API

Unit conversions, part of the nmeasim::core library.

Internal state is kept in the units marine users think in: degrees, knots, metres and degrees Celsius. Encoders convert to whatever a protocol demands with the constants and functions here: kilometres per hour and feet for NMEA 0183, metres per second and kelvin for Signal K.

Summary¶

Functions

Name	Description
`knots_to_kmh()`	Converts a speed from knots to kilometres per hour.
`knots_to_mps()`	Converts a speed from knots to metres per second.
`mps_to_knots()`	Converts a speed from metres per second to knots.
`metres_to_feet()`	Converts a length from metres to international feet.
`metres_to_fathoms()`	Converts a length from metres to fathoms.
`celsius_to_kelvin()`	Converts a temperature from degrees Celsius to kelvin.

Variables

Name	Description
`kMetresPerNauticalMile`	Metres in one international nautical mile, exact by definition.
`kSecondsPerHour`	Seconds in one hour.
`kFeetPerMetre`	International feet in one metre: 1 / 0.3048, rounded to double precision.
`kFathomsPerMetre`	Fathoms of six international feet in one metre: 1 / 1.8288, rounded to double precision.
`kKilometresPerHourPerKnot`	Kilometres per hour in one knot, exact by definition of the nautical mile.
`kMetresPerSecondPerKnot`	Metres per second in one knot: 1852 / 3600.
`kKelvinOffset`	Kelvin value of 0 degrees Celsius, exact by definition.

Functions¶

knots_to_kmh()¶

double knots_to_kmh(double knots) noexcept

Converts a speed from knots to kilometres per hour.

Parameters

Name	Type	Description
`knots`	`double`	Speed in knots.

Returns double: The speed in kilometres per hour.

Declared in src/core/include/nmeasim/core/units.hpp:38

knots_to_mps()¶

double knots_to_mps(double knots) noexcept

Converts a speed from knots to metres per second.

Parameters

Name	Type	Description
`knots`	`double`	Speed in knots.

Returns double: The speed in metres per second.

Declared in src/core/include/nmeasim/core/units.hpp:46

mps_to_knots()¶

double mps_to_knots(double mps) noexcept

Converts a speed from metres per second to knots.

Parameters

Name	Type	Description
`mps`	`double`	Speed in metres per second.

Returns double: The speed in knots.

Declared in src/core/include/nmeasim/core/units.hpp:54

metres_to_feet()¶

double metres_to_feet(double metres) noexcept

Converts a length from metres to international feet.

Parameters

Name	Type	Description
`metres`	`double`	Length in metres.

Returns double: The length in feet.

Declared in src/core/include/nmeasim/core/units.hpp:62

metres_to_fathoms()¶

double metres_to_fathoms(double metres) noexcept

Converts a length from metres to fathoms.

Parameters

Name	Type	Description
`metres`	`double`	Length in metres.

Returns double: The length in fathoms.

Declared in src/core/include/nmeasim/core/units.hpp:70

celsius_to_kelvin()¶

double celsius_to_kelvin(double celsius) noexcept

Converts a temperature from degrees Celsius to kelvin.

Parameters

Name	Type	Description
`celsius`	`double`	Temperature in degrees Celsius.

Returns double: The temperature in kelvin.

Declared in src/core/include/nmeasim/core/units.hpp:78

Variables¶

kMetresPerNauticalMile¶

double kMetresPerNauticalMile{1852.0}

Metres in one international nautical mile, exact by definition.

Declared in src/core/include/nmeasim/core/units.hpp:20

kSecondsPerHour¶

double kSecondsPerHour{3600.0}

Seconds in one hour.

Declared in src/core/include/nmeasim/core/units.hpp:22

kFeetPerMetre¶

double kFeetPerMetre{3.280839895013123}

International feet in one metre: 1 / 0.3048, rounded to double precision.

Declared in src/core/include/nmeasim/core/units.hpp:24

kFathomsPerMetre¶

double kFathomsPerMetre{0.5468066491688539}

Fathoms of six international feet in one metre: 1 / 1.8288, rounded to double precision.

Declared in src/core/include/nmeasim/core/units.hpp:26

kKilometresPerHourPerKnot¶

double kKilometresPerHourPerKnot{1.852}

Kilometres per hour in one knot, exact by definition of the nautical mile.

Declared in src/core/include/nmeasim/core/units.hpp:28

kMetresPerSecondPerKnot¶

double kMetresPerSecondPerKnot{kMetresPerNauticalMile / kSecondsPerHour}

Metres per second in one knot: 1852 / 3600.

Declared in src/core/include/nmeasim/core/units.hpp:30

kKelvinOffset¶

double kKelvinOffset{273.15}

Kelvin value of 0 degrees Celsius, exact by definition.

Declared in src/core/include/nmeasim/core/units.hpp:32