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 digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete global grid. DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally produced relief maps. A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs.
Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps.
An orthophoto, orthophotograph, orthoimage or orthoimagery is an aerial photograph or satellite imagery geometrically corrected ("orthorectified") such that the scale is uniform: the photo or image follows a given map projection. Unlike an uncorrected aerial photograph, an orthophoto can be used to measure true distances, because it is an accurate representation of the Earth's surface, having been adjusted for topographic relief, lens distortion, and camera tilt.
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 National Map is a collaborative effort of the United States Geological Survey (USGS) and other federal, state, and local agencies to improve and deliver topographic information for the United States. The purpose of the effort is to provide "...a seamless, continuously maintained set of public domain geographic base information that will serve as a foundation for integrating, sharing, and using other data easily and consistently".
Geotagging, or GeoTagging, is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RSS feeds and is a form of geospatial metadata. This data usually consists of latitude and longitude coordinates, though they can also include altitude, bearing, distance, accuracy data, and place names, and perhaps a time stamp.
SOCET SET is a software application that performs functions related to photogrammetry. It is developed and published by BAE Systems. SOCET SET was among the first commercial digital photogrammetry software programs. Prior to the development of digital solutions, photogrammetry programs were primarily analog or custom systems built for government agencies.
The American Society for Photogrammetry and Remote Sensing (ASPRS) is an American learned society devoted to photogrammetry and remote sensing. It is the United States' member organization of the International Society for Photogrammetry and Remote Sensing. Founded in 1934 as American Society of Photogrammetry and renamed in 1985, the ASPRS is a scientific association serving over 7,000 professional members around the world. As a professional body with oversight of specialists in the arts of imagery exploitation and photographic cartography. Its official journal is Photogrammetric Engineering & Remote Sensing (PE&RS), known as Photogrammetric Engineering between 1937 and 1975.
A "quadrangle" is a topographic map produced by the United States Geological Survey (USGS) covering the United States. The maps are usually named after local physiographic features. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas quad". A quadrangle is defined by north and south boundaries of constant latitude, and by east and west boundaries of constant longitude.
A stereoplotter uses stereo photographs to determine elevations. It has been the primary method to plot contour lines on topographic maps since the 1930s. Although the specific devices have advanced technologically, they are all based on the apparent change in position of a feature in the two stereo photographs.
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 Ethiopian Mapping Agency (EMA) is an Ethiopian government agency, a department within the Ministry of Finance and Cooperation, that is responsible for cartographic mapping and remote sensing activities in Ethiopia. The EMA has expanded its operation to include a comprehensive map revision program in addition to various phases of digital mapping and information technology.
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 Digital Line Graph (DLG) is a cartographic map feature represented in digital vector form that is distributed by the U.S. Geological Survey (USGS). DLGs are collected from USGS maps and are distributed in large, intermediate and small scale with up to nine different categories of features, depending on the scale. They come in optional and Spatial Data Transfer Standard (SDTS) format and are topologically structured for use in mapping and geographic information system (GIS) applications.
TopoFlight is a three-dimensional flight planning software for photogrammetric flights.
Major James Warren Bagley was an American aerial photographer, topographic engineer and inventor.
Geophotography is a subfield of geology that involves the use of photography or other imaging techniques in the visible or near-visible spectrum to realistically record objects, features, and processes of geological significance. Ultimately geophotography is motivated by a scientific comprehension or question and serves to accomplish a specific, useful goal in furthering the understanding of the aspect of geology that it addresses. However, crossover does occur from documentary to more artistic styles. As geology is, broadly, the study of the Earth, and often entails the study of large-scale features such as mountains and mountain belts, there is significant overlap between geophotography and landscape photography especially.
