Units of area
Units of area are essential measurements used to quantify land, evolving significantly throughout history and across cultures. Historically, these units have played a crucial role in defining land ownership, taxation, and agricultural practices. Ancient civilizations, including the Mesopotamians, Egyptians, Greeks, and Romans, developed various systems to measure land area, often based on practical agricultural use, such as the amount of land a team of oxen could plow in a day. For instance, the Greek system utilized the plethron, while Romans employed units like the acre and square foot.
During the medieval period, common measurements such as the perch, rood, and acre were standardized in Europe, with specific terms reflecting the land’s productivity and the number of families it could support. Different regions also adopted unique measures; for example, the Chinese and Japanese had their own systems, relevant for measuring smaller areas rather than large tracts of land.
In contemporary times, the metric system has become widely adopted globally, with the square meter (m²) serving as the standard unit of area. Meanwhile, the United States tends to use the US customary system, which includes units like square feet and square miles. Understanding these units is vital for diverse applications, including land management, real estate, and agriculture, reflecting a long history of human interaction with the environment.
Units of area
- SUMMARY: Numerous units of area have been used throughout history for measuring land.
Specific measurements of land area date back to ancient times to define land ownership (for the purposes of taxation, among other reasons). Some of these measurements are still used in the twenty-first century.
Ancient Units of Measurement
In Mesopotamia, land area was divided into a bur (an estate), which covered about 64,800 square meters. The bur, in turn, was divided into iku (fields), each covering about 3600 square meters. Further measurements and sub-divisions are recorded on surviving land documents. The Egyptians also had their own system based on the kha-ta (100,000 square cubits), which was divided into 10 setat, which consisted of 10 kha (1000 square cubits, or 275.65 square meters).
The Romans had a very specific system of measuring land, with the basic measure being an actus quadratus (acre), which covered about 1260 square meters. Smaller measurements were described as a pes quadratus (square foot) or scripulum (or square perch). These measurements were based on the pes (foot) being the basic unit of measurement throughout the Roman Empire, a length that was fixed throughout the Empire.
By contrast, the Greeks used a different system of land measurement by which land was divided into a plethron—a variable area of land that consisted of the amount of land a yoke of oxen were able to plough in a single day. As a result, the exact measurement varied from some parts of Greece to other parts (and indeed for different parts of a city), although it was thought to approximate to about four English acres. In rocky and hilly areas, the land area was larger than in other parts of the city. This method of measuring land area—based on what could be done with it—is quite different to the Roman system and largely emerged from a method of equitable taxation by which those with poorer land could be taxed fairly alongside those with more fertile land.
The Anglo-Saxons later followed this Greek concept of land measurement in England, using the “hide” as a measure of land. This measurement was used in the Domesday Book in 1086 and continued until the end of the twelfth century. Traditionally, it was thought that a hide consisted of the land needed to support ten families because it is used instead of the term terra x familiarum (land of ten families) in the Anglo-Saxon version of Bede’s ecclesiastical history. In Scotland during the same period, the term groatland was used to describe the land that could be rented for a particular coin—in this case, a groat. It would represent a larger area for poorer agricultural land than for richer land.
Medieval Era
By medieval times, in Europe and especially England, the terms of measuring land were standardized, and these tended to follow the Roman measurements of a “perch,” a “rood,” and an “acre.” Despite these measures (although the “hide” was being phased out), there were other measures, including the “carucate,” which covered the land that an eight-ox team could plough in a year (approximately 120 acres); a “virgate,” which covered land that could be plowed by two oxen in a year (about 30 acres); and a “bovate,” which covered the land that a single ox could plough in a year. There was also an area known as a “knight’s fee,” which was the land expected to be able to produce a single-armed soldier in times of war. Although early in medieval England, an acre was supposed to be the land that could be plowed in a single day, by late medieval times, it had been formalized as 4,840 square yards.
Other Systems of Measuring Area
Elsewhere in the world, many places had their own system of measuring area. The Chinese people based their system on the li (7.9 square yards), the fen (10 li), the mu (10 fen), the shi (10 mu), and the qing (10 shi). Japanese people also had a system of measurement by tsubo, which covered the land that was the same size as two tatami mats (about 3.306 square meters). In Korea, there is a similar measure called the pyeong, which covers 3.3058 square meters. These measures are generally used to measure the size of rooms and buildings rather than large areas of land. The tsubo and the pyeong are both still used in the twenty-first century to help describe the size of houses or apartments for sale, in the same way as the term “square” is used by Australian estate agents (approximating to 100 square feet, or 9.29 square meters).
Modern Measurement
The metric system was devised during the 1790s following the French Revolution in an attempt to standardize measurements. The French adopted the metric system after Napoleon Bonaparte came to power in 1799. The modern metric system focuses on the meter as the main measurement of length and the square meter (m2) as the measurement of area, as documented by the International System of Units. This is used throughout most of the world in the twenty-first century. These units include millimeters (mm2), square centimeters (cm2), and square kilometers (km2). In the United States, area is usually measured using the US customary system of measurement, which was based on the British Imperial system. Units of measurement include square feet (ft2), square inches (in2), square yards (yd2) and square miles (mi2).
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