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Isothetic polygon

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionJan 24, 2024
Entity authorityQ6086407
Source-derived summary

An isothetic polygon is a polygon whose alternate sides belong to two parametric families of straight lines which are pencils of lines with centers at two points (possibly the point at infinity). The most well-known example of isothetic polygons are rectilinear polygons, and the former term is commonly used as a synonym for the latter one.

Etymology and history

The term is produced from Greek roots: iso- for "equal, same, similar" and thetos (position, placement), i.e., the term is supposed to mean "polygon with similarly placed sides".

The term was suggested during the early years of the computational geometry. Much emphasis was placed on the development of efficient algorithms for operations with orthogonal polygons, since the latter ones had an important application: representation of shapes in integrated circuit mask layouts due to their simplicity for design and manufacturing. It was observed that the efficiency of many geometric algorithms for orthogonal polygons does not really depend on the fact that their sides meet at right angles, but rather on the fact that their sides are naturally split into two alternating sets (of vertical and horizontal segments).

Sets of isothetic polygons

In many applications of computational geometry, when a problem is stated for a set of rectilinear polygons, it is very often implicitly assumed that these polygons have the same alignment (in fact, aligned to the same orthogonal coordinate axes), and hence the term "isothetic polygons" would be less ambiguous. In the context of digital geometry, isothetic polygons are practically axis-parallel and have integer coordinates of their vertices.

References

Franco P. Preparata and Michael Ian Shamos (1985). Computational Geometry - An Introduction.

Editorial summary

The public source identifies “Isothetic polygon” as open-knowledge reference entry. This brief keeps that definition visible, then builds a research path around Isothetic, polygon and Open-knowledge.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current lead gives the account dated anchors—1985—that can be checked directly. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Isothetic, polygon and Open-knowledge providing the first useful test.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jan 24, 2024. The linked authority identifier is Q6086407. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1985.

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Source & attribution

This entry incorporates text from Isothetic polygon” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.