In modern mapping, a topographic map or topographic sheet is a type of map characterized by large-scale detail and quantitative representation of relief features, usually using contour lines, but historically using a variety of methods. Traditional definitions require a topographic map to show both natural and artificial features. A topographic survey is typically based upon a systematic observation and published as a map series, made up of two or more map sheets that combine to form the whole map. A topographic map series uses a common specification that includes the range of cartographic symbols employed, as well as a standard geodetic framework that defines the map projection, coordinate system, ellipsoid and geodetic datum. Official topographic maps also adopt a national grid referencing system.
A circle of latitude or line of latitude on Earth is an abstract east–west small circle connecting all locations around Earth at a given latitude coordinate line.
A projected coordinate system – also called a projected coordinate reference system, planar coordinate system, or grid reference system – is a type of spatial reference system that represents locations on Earth using Cartesian coordinates (x, y) on a planar surface created by a particular map projection. Each projected coordinate system, such as "Universal Transverse Mercator WGS 84 Zone 26N," is defined by a choice of map projection (with specific parameters), a choice of geodetic datum to bind the coordinate system to real locations on the earth, an origin point, and a choice of unit of measure. Hundreds of projected coordinate systems have been specified for various purposes in various regions.
The Ordnance Survey National Grid reference system (OSGB), also known as British National Grid (BNG), is a system of geographic grid references used in Great Britain, distinct from latitude and longitude.
A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults, folds, are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features.
The Universal Transverse Mercator (UTM) is a map projection system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means it ignores altitude and treats the earth surface as a perfect ellipsoid. However, it differs from global latitude/longitude in that it divides earth into 60 zones and projects each to the plane as a basis for its coordinates. Specifying a location means specifying the zone and the x, y coordinate in that plane. The projection from spheroid to a UTM zone is some parameterization of the transverse Mercator projection. The parameters vary by nation or region or mapping system.
The World Geographic Reference System (GEOREF) is a geocode, a grid-based method of specifying locations on the surface of the Earth. GEOREF is essentially based on the geographic system of latitude and longitude, but using a simpler and more flexible notation. GEOREF was used primarily in aeronautical charts for air navigation, particularly in military or inter-service applications, but it is rarely seen today. However, GEOREF can be used with any map or chart that has latitude and longitude printed on it.
The United States National Grid (USNG) is a multi-purpose location system of grid references used in the United States. It provides a nationally consistent "language of location", optimized for local applications, in a compact, user friendly format. It is similar in design to the national grid reference systems used in other countries. The USNG was adopted as a national standard by the Federal Geographic Data Committee (FGDC) of the US Government in 2001.
The National Maps of Switzerland, also referred to as the Swisstopo maps, are a set of official map series designed, edited and distributed by Swisstopo, the Swiss Federal Office of Topography. Each map series is based on an oblique, conformal, cylindrical projection, with a Swiss Coordinate system. All maps are updated in a complete cycle of about six years.
Geohash is a public domain geocode system invented in 2008 by Gustavo Niemeyer which encodes a geographic location into a short string of letters and digits. Similar ideas were introduced by G.M. Morton in 1966. 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.
The Instituto Geográfico Nacional (IGN), or National Geographic Institute is a Spanish government agency, dependent on the Spanish Ministry of Public Works. It is the national mapping agency for Spain, together with the Centro Nacional de Información Geográfica (CNIG).
The Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose, which was to map Scotland in the wake of the Jacobite rising of 1745. There was also a more general and nationwide need in light of the potential threat of invasion during the Napoleonic Wars. Since 1 April 2015, the Ordnance Survey has operated as Ordnance Survey Ltd, a government-owned company, 100% in public ownership. The Ordnance Survey Board remains accountable to the Secretary of State for Science, Innovation and Technology. It was also a member of the Public Data Group.
The 68th parallel north is a circle of latitude that is 68 degrees north of the Earth's equatorial plane, in the Arctic. It crosses the Atlantic Ocean, Europe, Asia and North America.
The 80th parallel north is a circle of latitude that is 80 degrees north of the Earth's equatorial plane, and 10 degrees south of the North Pole, in the Arctic. It crosses the Atlantic Ocean, Europe, Asia, the Arctic Ocean and North America.
A national mapping agency is an organisation, usually publicly owned, that produces topographic maps and geographic information of a country. Some national mapping agencies also deal with cadastral matters.
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the United States government whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March 3, 1879, to study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The agency also makes maps of extraterrestrial planets and moons based on data from U.S. space probes.
A map series is a group of topographic or thematic charts or maps usually having the same scale and cartographic specifications, and with each sheet appropriately identified by its publisher as belonging to the same series.
Survey of Pakistan is the sole national mapping and land surveying government agency of Pakistan. Its head of department is titles as "Surveyor General of Pakistan".
The Open Location Code (OLC) is a geocode based in a system of regular grids for identifying an area anywhere on the Earth. It was developed at Google's Zürich engineering office, and released late October 2014. Location codes created by the OLC system are referred to as "plus codes".
The Arani, also known as Araniar or Araniyar, is a 108 km long river in India. It flows through the states of Tamil Nadu and Andhra Pradesh.
