Quadrat

A quadrat is a plot used in ecology and geography to isolate a standard unit of area for study of the distribution of an item over a large area. While originally rectangular, modern quadrats can be rectangular, circular, irregular, etc.,. The quadrat is suitable for sampling plants, slow-moving animals (such as millipedes and insects), and some aquatic organisms.

When an ecologist wants to know how many organisms there are in a particular habitat, it would not be feasible to count them all. Instead, they would be forced to count a smaller representative part of the population, called a sample. Sampling of plants or animals that do not move much (such as snails), can be done using a sampling square called a quadrat. A suitable size of a quadrat depends on the size of the organisms being sampled. For example, to count plants growing on a school field, one could use a quadrat with sides 0.5 or 1 meter in length.

It is important that sampling in an area is carried out at random, to avoid bias. For example, if you were sampling from a school field, but for convenience only placed quadrats next to a path, this might not give a sample that was representative of the whole field. It would be an unrepresentative, or biased, sample. One way one can sample randomly is to place the quadrats at coordinates on a numbered grid. Quadrats may also be used sampling oneself.

Quadrat (disambiguation)

Quadrat may refer to:

See also

Quadrat (hieroglyph block)

A quadrat block (or quadrate block) is a virtual rectangle or square in Egyptian hieroglyphic text.

The glyphs (hieroglyphs) can be variable in number within the virtual block, though they are often proportioned according to variable standardized rules of scribal methods.

The definition for the block in Illustrated Hieroglyphics Handbook by Schumann-Antelme and Rossini, is: "A 'quadrate' is a virtual square, which although not drawn, guides the hand of the scribe. Hieroglyphs must be aesthetically positioned within the quadrate and their size must be proportioned accordingly. They form groups that are pleasing to the eye and based on the laws of balance."

Rosetta Stone closeup

An example of 5 lines of text from the Rosetta Stone, (lines 9, 10, 11, 12, 13), shows a width of about six to seven virtual blocks. Line 12, (fourth line) is illustrative of the variable size, in this case the widths, of the 'virtual quadrate blocks'.

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(See: N-red crown (n hieroglyph), N-water ripple (n hieroglyph))