Units of scale


All scale units have helper methods ->asUnity(), ->add(), ->subtract(), ->multiply() and ->divide()


You can access the list of supported scale units at runtime using Scale::getSupportedSRIDs() or Scale::getSupportedSRIDsWithHelp()


new Unity(float $number)
Scale::makeUnit(float $number, Scale::EPSG_UNITY)
Scale::makeUnit(float $number, 'urn:ogc:def:uom:EPSG::9201')

SI coherent derived unit (standard unit) for dimensionless quantity.


new Coefficient(float $number)
Scale::makeUnit(float $number, Scale::EPSG_COEFFICIENT)
Scale::makeUnit(float $number, 'urn:ogc:def:uom:EPSG::9203')

Used when parameters are coefficients. They inherently take the units which depend upon the term to which the coefficient applies.

Parts per billion

new PartsPerBillion(float $number)
Scale::makeUnit(float $number, Scale::EPSG_PARTS_PER_BILLION)
Scale::makeUnit(float $number, 'urn:ogc:def:uom:EPSG::1028')

Billion is internationally ambiguous, in different languages being 1E+9 and 1E+12. One billion taken here to be 1E+9.

Parts per million

new PartsPerMillion(float $number)
Scale::makeUnit(float $number, Scale::EPSG_PARTS_PER_MILLION)
Scale::makeUnit(float $number, 'urn:ogc:def:uom:EPSG::9202')