Product Code Database
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about and one hectare contains about . In 1795, when the metric system was introduced, the are was defined as 100 , or one square decametre, and the hectare ("hecto-" + "are") was thus 100 ares or km2 ( square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units (), the are was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decare daa () and are (100 m2) are not officially "accepted for use", they are still used in some contexts.
| +Comparison of area units !Unit | SI |
| 1 ca | 1 m2 |
| 1 a | 100 m2 |
| 1 ha | 10,000 m2 |
| 100 ha | 1 km2 |
| 0.3861 sq mi | 1 km2 |
| 2.471 acre | 1 ha |
| 1 ha | |
| 1 sq mi | 259.0 ha |
| 1 acre | 0.4047 ha |
has an area of about one hectare. ]]
The hectare ( ), although not a unit of SI, is the only named unit of area that is accepted for use with SI units. Chapter 5. The name was coined in French, from the Latin ārea. Oxford English Dictionary, 1st edition s.v. In practice the hectare is fully derived from the SI, being equivalent to a square hectometre. It is widely used throughout the world for the measurement of large areas of land, and it is the legal unit of measure in domains concerned with land ownership, planning, and land management, including law (deed), agriculture, forestry, and town planning throughout the European Union, New Zealand and Australia (since 1970). However, the United Kingdom, the United States, Myanmar (Burma), and to some extent Canada, use the acre instead of the hectare for measuring surface or land area.
Some countries that underwent a general conversion from traditional measurements to Metric system measurements (e.g. Canada) required a resurvey when units of measure in legal descriptions relating to land were converted to metric units. Others, such as South Africa, published conversion factors which were to be used particularly "when preparing consolidation diagrams by compilation".
In many countries, metrification redefined or clarified existing measures in terms of metric units. The following legacy units of area have been redefined as being equal to one hectare: Britannica.com, unit of measurement, accessed 30 October 2009
In 1960, when the metric system was updated as the International System of Units (SI), the are did not receive international recognition. The International Committee for Weights and Measures () makes no mention of the are in the 2019 edition of the SI brochure, but classifies the hectare as a "Non-SI unit accepted for use with the International System of Units".
In 1972, the European Economic Community (EEC) passed directive 71/354/EEC, which catalogued the units of measure that might be used within the Community. The units that were catalogued replicated the recommendations of the CGPM, supplemented by a few other units including the are (and implicitly the hectare) whose use was limited to the measurement of land.
In Russian language and some other languages of the former Soviet Union, the are is called sotka (сотка: 'a hundred', i.e. 100 m2 or hectare). It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large. Many Russian dachas are 6 ares in size (in Russian, шесть соток).
One hectare is also equivalent to:
is a combination of ヘクタール (), the Japanese translation of "hectare".
|
|
