Units is a PHP package consisting of classes representing units of measure.
The following units are provided:
$ composer require marando/units
An Angle can easily be created from degree or radian values as such:
Angle::deg(180); // create angle from degrees
Angle::rad(3); // create angle from radiansYou can also create an Angle from degree, minute and second components:
echo Angle::dms(180, 10, 4); // create angle from ° ' "
echo Angle::dms(0, 0, 4); // create angle from just secondsYou can also create an Angle from a number of arcmin, arcsec and mas:
echo Angle::arcmin(15); // Create from arcmin Result: 0°15'0".0
echo Angle::arcsec(50); // Create from arcsec Result: 0°0'50".0
echo Angle::mas(310); // Create from mas Result: 0°0'0".31The following properties can be obtained from Angle instances:
$angle = Angle::dms(180, 30, 0);
echo $angle->deg; // degrees Output: 180.5
echo $angle->rad; // radians Output: 3.1503192998498
echo $angle->d; // degree component Output: 180
echo $angle->m; // minute component Output: 30
echo $angle->s; // second component Output: 0If you need to normalize an Angle to a specific interval you can do it as such:
echo Angle::deg(480)->norm(0, 360); // normalize to [0, +2π] Output: 120°0'0".0
echo Angle::deg>norm(0, 180); // normalize to [0, +π] Output: 160°0'0".0
echo Angle::deg->norm(-360, 360); // normalize to [-2π, +2π] Output: -360°0'0".0The Angle object supports the mathematical operations addition, subtraction and multiplication as well as negation.
echo Angle::deg(90)->add(Angle::fromDeg(90)); // addition Output: 180°0'0".0
echo Angle::deg(90)->subtract(Angle::fromDeg(90)); // subtraction Output: 180°0'0".0
echo Angle::deg(90)->multiply(Angle::fromDeg(3)); // multiplication Output: 270°0'0".0
echo Angle::deg(90)->negate(); // negation Output: -90°0'0".0By default the string value of an Angle is expressed in the format 180°0'0".0 up to three decimal places. You can use the round method to specify the number of decimal places to display:
echo Angle::rad(3)->round(0); // round to nearest second Output: 171°53'14"
echo Angle::rad(3)->round(3); // round to 3 places Output: 171°53'14".419
echo Angle::rad(3)->round(10); // round to 10 places Output: 171°53'14".4187412891// Metric
echo Distance::mm(1); // create distance from millimeters Output: 1.000 mm
echo Distance::cm(1); // create distance from centimeters Output: 1.000 cm
echo Distance::m(1); // create distance from meters Output: 1.000 m
echo Distance::km(1); // create distance from kilometers Output: 1.000 km
// Imperial
echo Distance::mi(1); // create distance from miles Output: 1.000 mi
// Astronomy
echo Distance::au(1); // create distance from astronomical units Output: 1.000 AU
echo Distance::pc(1); // create distance from parsecs Output: 1.000 pc
echo Distance::ly(1); // create distance from light-years Output: 1.000 lyThe Distance object supports the mathematical operations addition and subtraction.
$a = Distance::km(103);
$b = Distance::km(7);
$a->add($b); // Output: 110.000 km
$a->subtract($b); // Output: 96.000 kmDistances can be created from astronomical measures of parallax:
// Create distance from parallax of 470 milliarcsec
echo $d = Distance::parallax(Angle::mas(470))
echo $d->ly;
echo $d->pc;
echo $d->au;Output:
2.128 pc
6.9394973982286
2.1276595744681
438861.2898874
By default the string value of a Distance is expressed using three decimal places. You can use the round method to specify the number of decimal places to display:
echo Distance::km(2/3)->round(0); // round to nearest unit Output: 1 km
echo Distance::km(2/3)->round(3); // round to 3 places Output: 0.667 km
echo Distance::km(2/3)->round(10); // round to 10 places Output: 0.6666666667 kmOnce you have created a Distance instance, conversion between different units is simple:
echo Distance::mi(1)->km; // get the raw kilometer value Output: 1.609344
echo Distance::mi(1)->setUnit('km'); // set units to kilometers Output: 1.609 kmValid values for the setUnit() are as follows: mm, cm, m, km, mi, au, pc, and ly
Sometimes you may wish to provide the parameters for the definition of a distance unit (usually in the case of historic applications). For example, you may wish to create a distance of 5 astronomica units, but using the old definition of 149597870.691 kilometers/AU instead of the current definition. This is possible as follows:
// Create distance with default and custom AU definitions
$default = Distance::au(1.5);
$custom = Distance::au(1.5, Distance::km(149597870.691));
// AU is the same since that's what we supplied
echo $default; // Output: 1.500 AU
echo $custom; // Output: 1.500 AU
// Conveersions are different depending on the AU definition
echo $default->km; // Output: 224396806.05
echo $custom->km; // Output: 224396806.0365Overriding definition parameters is currenly only possible for astronomical units, light-years and parsecs.
Pressure instances can be created like this:
Pressure::Pa(100); // Create pressure from Pascals
Pressure::inHg(100); // Create pressure from inches of mercury
Pressure::mbar(100); // Create pressure from millibarsecho Pressure::Pa(100)->inHg;
echo Pressure::Pa(100)->setUnit('inHg');
echo Pressure::mbar(1000)->Pa;
echo Pressure::mbar(1000)->setUnit('Pa');Output:
0.029533372711164
0.029533372711164 inHg
100000
100000 Pa
Valid values for the setUnit() are as follows: Pa, inHg, and mbar
Temperature instances can be created like this:
Temperature::C(100); // Create temperature from Celcius
Temperature::F(-32); // Create temperature from Fahrenheit
Temperature::K(0); // Create temperature from Kelvinsecho Temperature::C(100)->F;
echo Temperature::C(100)->setUnit('F');
echo Temperature::F(32)->C;
echo Temperature::F(32)->setUnit('C');
echo Temperature::K(0)->C;
echo Temperature::K(0)->setUnit('C');Output:
212
212°F
0
0°C
-273.15
-273.15°C
Valid values for the setUnit() are as follows: C, F, and K
Time instances are simple to create:
echo Time::hms(1, 10, 15); // create time from h/m/s components Output: 1ʰ10ᵐ15ˢ
echo Time::sec(30); // create time from seconds Output: 30 sec
echo Time::min(4); // create time from minutes Output: 5 min
echo Time::hours(2); // create time from hours Output: 2 hour
echo Time::days(1); // create time from days Output: 1 dayBy default the string value of a Time instance is expressed using three decimal places. You can use the round method to specify the number of decimal places to display:
echo Time::days(2/3)->round(0); // round to nearest unit Output: 1 day
echo Time::days(2/3)->round(3); // round to 3 places Output: 0.667 days
echo Time::days(2/3)->round(10); // round to 10 places Output: 0.6666666667 daysOnce you have created a Time instance, conversion between different units is simple:
echo Time::days(0.54921)->min; // get the raw minute value Output: 790.8624
echo Time::days(0.54921)->setUnit('min'); // set units to minutes Output: 790.862 minValid values for the setUnit() are as follows: sec, min, hours, days, hms
The Time object supports the mathematical operations addition and subtraction.
echo Time::sec(90)->add(Time::min(30)); // addition Output: 0ʰ31ᵐ30ˢ
echo Time::sec(90)->subtract(Time::min(30)); // subtraction Output: -0ʰ28ᵐ30ˢThe hour, minute and second components of a Time instance can be obtained as shown:
$time = Time::sec(83028);
echo $time->h; // degree component Output: 21
echo $time->m; // minute component Output: 8
echo $time->s; // second component Output: 43A Velocity instance can be created two ways:
- By providing distance and time components, and
- By using a pre-defined static constructor
echo new Velocity(Distance::m(5), Time::sec(1)); // Method 1 Output: 5 m/s
echo Velocity::ms(5); // Method 2 Output: 5 m/sThe first method is especially powerful for cases with non-uniform time denominators. By creating a velocity instance this way you can for example easily resolve unknown velocities from observational data:
$velocity = new Velocity(Distance::m(507), Time::sec(14.532));
echo $velocity->ms; // in m/s Output: 34.888521882742
echo $velocity->setUnit('ms'); // in m/s Output: 34.889 m/s
echo $velocity->mph; // in mph Output: 78.043400775639
echo $velocity->setUnit('mph'); // in mph Output: 78.043 mphAs per the second method, the following pre-defined unit constructors exist:
| Method | Unit | Description |
|---|---|---|
Velocity::kmd() |
km/d | kilometers per day |
Velocity::kmh() |
km/h | kilometers per hour |
Velocity::kms() |
km/s | kilometers per second |
Velocity::mph() |
mph | miles per hour |
Velocity::ms() |
m/s | meters per second |
Velocity::pcy() |
pc/y | parsecs per year |
By default the string value of a Velocity instance is expressed using three decimal places. You can use the round method to specify the number of decimal places to display:
echo Velocity::mph(2/3)->round(0); // round to nearest unit Output: 1 mph
echo Velocity::mph(2/3)->round(3); // round to 3 places Output: 0.667 mph
echo Velocity::mph(2/3)->round(10); // round to 10 places Output: 0.6666666667 mphOnce you have created a Velocity instance, conversion between different units is simple:
echo Velocity::mph(60)->ms; // get the raw m/s value Output: 26.8224
echo Velocity::mph(60)->setUnit('m/s'); // set units to m/s Output: 26.822 m/sValid values for the setUnit() are as follows: km/d, km/h, km/s, mph, m/s, and pc/y
You can get the distance and time components of a Velocity instance as follows:
echo Velocity::kmh(10)->dist; // get distance component Output: 10.000 km
echo Velocity::kmh(10)->time; // get time component Output: 1 hourThe Velocity object has two methods distance() and time() which can find a distance or time component provided the other. This is best described by example:
$v = Velocity::mph(60);
// Find distance traveled in 30 min at velocity $v
echo $v->dist(Time::min(30)) // Output: 30.000 mi
// Find time required to travel 120 miles at velocity $v
echo $v->time(Distance::mi(120)) // Output: 2 hours