Units of length

Tip

All length units have helper methods ->asMetres(), ->add(), ->subtract(), ->multiply() and ->divide()

Tip

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

Metre

new Metre(float $length)
Length::makeUnit(float $length, Length::EPSG_METRE)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9001')

SI base unit for length.

Centimetre

new Centimetre(float $length)
Length::makeUnit(float $length, Length::EPSG_CENTIMETRE)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::1033')

Kilometre

new Kilometre(float $length)
Length::makeUnit(float $length, Length::EPSG_KILOMETRE)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9036')

Millimetre

new Millimetre(float $length)
Length::makeUnit(float $length, Length::EPSG_MILLIMETRE)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::1025')

International (modern) foot

new Foot(float $length)
Length::makeUnit(float $length, Length::EPSG_FOOT)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9002')

\(\frac{3048}{10000}\) metres.

International link

new Link(float $length)
Length::makeUnit(float $length, Length::EPSG_LINK)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9098')

\(\frac{66}{100}\) international feet.

US survey foot

new USSurveyFoot(float $length)
Length::makeUnit(float $length, Length::EPSG_US_SURVEY_FOOT)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9003')

\(\frac{12}{39.37}\) metres. Now deprecated by NIST who would prefer you use metres (or international feet if you can’t)

British foot

British foot (Benoit 1895 B)

British chain (Benoit 1895 B)

Length::makeUnit(float $length, Length::EPSG_BRITISH_CHAIN_BENOIT_1895_B)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9062')

Used in West Malaysian mapping.

British foot (Sear’s 1922)

new BritishFoot1922Sears(float $length)
Length::makeUnit(float $length, Length::EPSG_BRITISH_FOOT_SEARS_1922)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9041')

Used in East Malaysian and older New Zealand mapping.

British yard (Sear’s 1922)

new BritishYard1922Sears(float $length)
Length::makeUnit(float $length, Length::EPSG_BRITISH_YARD_SEARS_1922)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9040')

3 British feet.

British chain (Sear’s 1922)

new BritishChain1922Sears(float $length)
Length::makeUnit(float $length, Length::EPSG_BRITISH_CHAIN_SEARS_1922)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9042')

66 British feet.

British foot (Sear’s 1922 truncated)

British chain (Sear’s 1922 truncated)

new BritishChain1922SearsTruncated(float $length)
Length::makeUnit(float $length, Length::EPSG_BRITISH_CHAIN_SEARS_1922_TRUNCATED)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9301')

66 British Feet. Used in metrication of Malaya RSO grid.

British foot (1936)

new BritishFoot1936(float $length)
Length::makeUnit(float $length, Length::EPSG_BRITISH_FOOT_1936)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9095')

Also used for metric conversions in Ireland.

Clarke’s foot

new ClarkeFoot(float $length)
Length::makeUnit(float $length, Length::EPSG_CLARKES_FOOT)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9005')

Used in older Australian, southern African & British West Indian mapping.

Clarke’s link

new ClarkeLink(float $length)
Length::makeUnit(float $length, Length::EPSG_CLARKES_LINK)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9039')

\(\frac{1}{100}\) Clarke’s chain. Used in older Australian, southern African & British West Indian mapping.

Clarke’s yard

new ClarkeYard(float $length)
Length::makeUnit(float $length, Length::EPSG_CLARKES_YARD)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9037')

3 Clarke’s feet. Used in older Australian, southern African & British West Indian mapping.

Gold Coast foot

new GoldCoastFoot(float $length)
Length::makeUnit(float $length, Length::EPSG_GOLD_COAST_FOOT)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9094')

Used in Ghana and some adjacent parts of British west Africa prior to metrication, except for the metrication of projection defining parameters when British foot (Sear’s 1922) used.

Indian foot

new IndianFoot(float $length)
Length::makeUnit(float $length, Length::EPSG_INDIAN_FOOT)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9080')

Indian Foot = 0.99999566 British feet.

Indian yard

new IndianYard(float $length)
Length::makeUnit(float $length, Length::EPSG_INDIAN_YARD)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9084')

3 Indian Feet.

German legal metre

new GermanLegalMetre(float $length)
Length::makeUnit(float $length, Length::EPSG_GERMAN_LEGAL_METRE)
Length::makeUnit(float $length, 'urn:ogc:def:uom:EPSG::9031')

Used in Namibia. Yes Namibia, no German mapping uses this.