|
Geohash 2014-01-13 Location
Geohash is a public domain geocode system invented in 2008 by Gustavo NiemeyerEvidences at the Wayback Machine: labix.org in 2008, the G. Niemeyer's blog announcing Geohash *an article about Geohash witnessing and citing G. Niemeyer works, before 2012 G. Niemeyer's post at forums.geocaching.com announcing Geohash in Feb. 2008 which encodes a geographic location into a short string of letters and digits. Similar ideas were introduced by G.M. Morton in 1966.G. M. Morton (196''"A Computer Oriented Geodetic Data Base and a New Technique in File Sequencing"''. Report in IBM Canada. It is a hierarchical spatial data structure which subdivides space into buckets of grid shape, which is one of the many applications of what is known as a Z-order curve, and generally space-filling curves. Geohashes offer properties like arbitrary precision and the possibility of gradually removing characters from the end of the code to reduce its size (and gradually lose precision). Geohashing guarantees t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Domain
The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, anyone can legally use or reference those works without permission. As examples, the works of William Shakespeare, Ludwig van Beethoven, Leonardo da Vinci and Georges Méliès are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by a country's copyright laws, and are therefore in the public domain; for example, in the United States, items excluded from copyright include the formulae of Newtonian physics, cooking recipes,Copyright Protection No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographical Coordinate System
The geographic coordinate system (GCS) is a spherical or ellipsoidal coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface. A full GCS specification, such as those listed in the EPSG and ISO 19111 standards, also includes a choice of geodetic datum (including an Earth ellipsoid), as different datums will yield different latitude and longitude values for the same location. History The invention of a geographic coordinate system is generally credited to Eratosthenes of Cyrene, who composed his now-lost ''Geography'' at the Library of Alexandria in the 3rd century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edge Case
An edge case is a problem or situation that occurs only at an extreme (maximum or minimum) operating parameter. For example, a stereo speaker might noticeably distort audio when played at maximum volume, even in the absence of any other extreme setting or condition. An edge case can be expected or unexpected. In engineering, the process of planning for and gracefully addressing edge cases can be a significant task, and yet this task may be overlooked or underestimated. Non-trivial edge cases can result in the failure of an object that is being engineered. They may not have been foreseen during the design phase, and they may not have been thought possible during normal use of the object. For this reason, attempts to formalize good engineering standards often include information about edge cases. Software engineering In programming, an edge case typically involves input values that require special handling in an algorithm behind a computer program. As a measure for validating th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Textual Representation
In literary theory, textuality comprises all of the attributes that distinguish the communicative content under analysis as an object of study. It is associated with structuralism and post-structuralism. Explanation Textuality is not just about the written word; it also comprises the placement of the words and the reader’s interpretation. There is not a set formula to describe a text’s textuality; it is not a simple procedure. This summary is true even though the interpretation that a reader develops from that text may decide the identity and the definitive meanings of that text. Textuality, as a literary theory, is that which constitutes a text in a particular way. The text is an undecidable (there is an inexistence of an effective or "strict" method of writing or structure). Aspects Being textual includes innumerable elements and aspects. Each and every form of text and text in that form of literature embraces and consists of its own individual and personal characteristi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geo URI Scheme
The geo URI scheme is a Uniform Resource Identifier (URI) scheme defined by the Internet Engineering Task Force's RFC 5870 (published 8 June 2010) as: a Uniform Resource Identifier (URI) for geographic locations using the 'geo' scheme name. A 'geo' URI identifies a physical location in a two- or three-dimensional coordinate reference system in a compact, simple, human-readable, and protocol-independent way. The current revision of the vCard specification supports geo URIs in a vCard's "GEO" property, and the GeoSMS standard uses geo URIs for geotagging SMS messages. Android based devices support geo URIs, although that implementation is based on a draft revision of the specification, and supports a different set of URI parameters and query strings. A geo URI is not to be confused with the former website of ''GeoURL'' (which had implemented ICBM addresses). Example A simple geo URI might look like: :geo:37.786971,-122.399677 where the two numerical values represent latitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parity (mathematics)
In mathematics, parity is the property of an integer of whether it is even or odd. An integer is even if it is a multiple of two, and odd if it is not.. For example, −4, 0, 82 are even because \begin -2 \cdot 2 &= -4 \\ 0 \cdot 2 &= 0 \\ 41 \cdot 2 &= 82 \end By contrast, −3, 5, 7, 21 are odd numbers. The above definition of parity applies only to integer numbers, hence it cannot be applied to numbers like 1/2 or 4.201. See the section "Higher mathematics" below for some extensions of the notion of parity to a larger class of "numbers" or in other more general settings. Even and odd numbers have opposite parities, e.g., 22 (even number) and 13 (odd number) have opposite parities. In particular, the parity of zero is even. Any two consecutive integers have opposite parity. A number (i.e., integer) expressed in the decimal numeral system is even or odd according to whether its last digit is even or odd. That is, if the last digit is 1, 3, 5, 7, or 9, then it is odd; other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positional Notation
Positional notation (or place-value notation, or positional numeral system) usually denotes the extension to any radix, base of the Hindu–Arabic numeral system (or decimal, decimal system). More generally, a positional system is a numeral system in which the contribution of a digit to the value of a number is the value of the digit multiplied by a factor determined by the position of the digit. In early numeral systems, such as Roman numerals, a digit has only one value: I means one, X means ten and C a hundred (however, the value may be negated if placed before another digit). In modern positional systems, such as the decimal, decimal system, the position of the digit means that its value must be multiplied by some value: in 555, the three identical symbols represent five hundreds, five tens, and five units, respectively, due to their different positions in the digit string. The Babylonian Numerals, Babylonian numeral system, base 60, was the first positional system to be deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base 32
Base32 is the base-32 numeral system. It uses a set of 32 digits, each of which can be represented by 5 bits (25). One way to represent Base32 numbers in a human-readable way is by using a standard 32-character set, such as the twenty-two upper-case letters A–V and the digits 0-9. However, many other variations are used in different contexts. The rest of this article discusses the use of Base32 for representing byte strings, not unsigned integer numbers, similar to the way Base64 works. This is an example of a Base32 representation using the previously described 32-character set ( IPFS CIDv1 in Base32 upper-case encoding): Advantages Base32 has a number of advantages over Base64: # The resulting character set is all one case, which can often be beneficial when using a case-insensitive filesystem, DNS names, spoken language, or human memory. # The result can be used as a file name because it cannot possibly contain the '/' symbol, which is the Unix path separator. # The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base 4
A quaternary numeral system is base-. It uses the digits 0, 1, 2 and 3 to represent any real number. Conversion from binary is straightforward. Four is the largest number within the subitizing range and one of two numbers that is both a square and a highly composite number (the other being 36), making quaternary a convenient choice for a base at this scale. Despite being twice as large, its radix economy is equal to that of binary. However, it fares no better in the localization of prime numbers (the smallest better base being the primorial base six, senary). Quaternary shares with all fixed- radix numeral systems many properties, such as the ability to represent any real number with a canonical representation (almost unique) and the characteristics of the representations of rational numbers and irrational numbers. See decimal and binary for a discussion of these properties. Relation to other positional number systems Relation to binary and hexadecimal As with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
