|
Digital Line Graph
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. Description DLGs are normally derived from USGS maps or USGS map-related sources. DLGs are distributed at three different scales: large-scale, which normally correspond to the USGS 7.5- by 7.5-minute, 1:24,000 and 1:25,000-scale topographic quadrangle map series, 1:63,360-scale for Alaska and 1:30,000-scale for Puerto Rico; intermediate scale, which are derived from the USGS 30- by 60-minute, 1:100,000-scale map series; and small-scale, which are derived from the USGS 1:2,000,000-scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
USGS Logo
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior 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 planets and moons, based on data from U.S. space probes. The sole scientific agency of the U.S. Department of the Interior, USGS is a fact-finding research organization with no regulatory responsibility. It is headquartered in Reston, Virginia, with major offices near Lakewood, Colorado; at the Denver Federal Center; and in NASA Research Park in California. In 2009, it employed about 8,670 people. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on its hundredth anniversary, was "Earth Science in the Public Servi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Geographic Coordinate System
A geographic coordinate system (GCS) is a spherical coordinate system, spherical or geodetic coordinates, geodetic coordinate system for measuring and communicating position (geometry), positions directly on Earth as latitude and longitude. It is the simplest, oldest, and most widely used type 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 Geodetic Parameter Dataset, 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 Cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Topological
Topology (from the Greek words , and ) is the branch of mathematics concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself. A topological space is a set endowed with a structure, called a ''topology'', which allows defining continuous deformation of subspaces, and, more generally, all kinds of continuity. Euclidean spaces, and, more generally, metric spaces are examples of topological spaces, as any distance or metric defines a topology. The deformations that are considered in topology are homeomorphisms and homotopies. A property that is invariant under such deformations is a topological property. The following are basic examples of topological properties: the dimension, which allows distinguishing between a line and a surface; compactness, which allows distinguishing between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hypsography
Hypsometry () is the measurement of the elevation and depth of features of Earth's surface relative to mean sea level. On Earth, the elevations can take on either positive or negative (below sea level) values. The distribution is theorised to be bimodal due to the difference in density between the lighter continental crust and denser oceanic crust. On other planets within this solar system, elevations are typically unimodal, owing to the lack of plate tectonics on those bodies. Hypsometric curve A hypsometric curve is a histogram or cumulative distribution function of elevations in a geographical area. Differences in hypsometric curves between landscapes arise because the geomorphic processes that shape the landscape may be different. When drawn as a 2-dimensional histogram, a hypsometric curve displays the elevation (''y'') on the vertical, y-axis and area above the corresponding elevation (''x'') on the horizontal or x-axis. The curve can also be shown in non-dimensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hydrography
Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities, including economic development, security and defense, scientific research, and environmental protection. History The origins of hydrography lay in the making of charts to aid navigation, by individual mariners as they navigated into new waters. These were usually the private property, even closely held secrets, of individuals who used them for commercial or military advantage. As transoceanic trade and exploration increased, hydrographic surveys started to be carried out as an exercise in their own right, and the commissioning of surveys was increasingly done by governments and special hydrographic offices. National organizations, particularly navies, realize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Border
Borders are generally defined as geography, geographical boundaries, imposed either by features such as oceans and terrain, or by polity, political entities such as governments, sovereign states, federated states, and other administrative division, subnational entities. Political borders can be established through warfare, colonization, or mutual agreements between the political entities that reside in those areas. Some borders—such as most states' internal administrative borders, or inter-state borders within the Schengen Area—are open border, open and completely unguarded. Most external political borders are partially or fully controlled, and may be crossed legally only at designated border checkpoints; adjacent Border control#Border zones, border zones may also be controlled. For the purposes of border control, airports and Port#Seaport, seaports are also classed as borders. Most countries have some form of border control to regulate or limit the movement of people, animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Public Land Survey System
The Public Land Survey System (PLSS) is the surveying method developed and used in the United States to plat, or divide, real property for sale and settling. Also known as the Rectangular Survey System, it was created by the Land Ordinance of 1785 to survey land ceded to the United States by the Treaty of Paris (1783), Treaty of Paris in 1783, following the end of the American Revolution. Beginning with the Seven Ranges in present-day Ohio, the PLSS has been used as the primary survey method in the United States. Following the passage of the Northwest Ordinance in 1787, the Surveyor General of the Northwest Territory platted lands in the Northwest Territory. The Surveyor General was later merged with the United States General Land Office, which later became a part of the U.S. Bureau of Land Management (BLM). Today, the BLM controls the survey, sale, and settling of lands acquired by the United States. History Originally proposed by Thomas Jefferson to create a nation of "yeom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Topological Space
In mathematics, a topological space is, roughly speaking, a Geometry, geometrical space in which Closeness (mathematics), closeness is defined but cannot necessarily be measured by a numeric Distance (mathematics), distance. More specifically, a topological space is a Set (mathematics), set whose elements are called Point (geometry), points, along with an additional structure called a topology, which can be defined as a set of Neighbourhood (mathematics), neighbourhoods for each point that satisfy some Axiom#Non-logical axioms, axioms formalizing the concept of closeness. There are several equivalent definitions of a topology, the most commonly used of which is the definition through open sets, which is easier than the others to manipulate. A topological space is the most general type of a space (mathematics), mathematical space that allows for the definition of Limit (mathematics), limits, Continuous function (topology), continuity, and Connected space, connectedness. Common types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
North American Datum
The North American Datum (NAD) is the Geodetic datum#Horizontal datum, horizontal datum now used to define the Geodesy, geodetic network in North America. A datum is a formal description of the shape of the Earth along with an "anchor" point for the coordinate system. In surveying, cartography, and land-use planning, two North American Datums are in use for making lateral or "horizontal" measurements: the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83). Both are geodetic reference systems based on slightly different assumptions and measurements. Vertical measurements, based on distances above or below Mean High Water (MHW), are calculated using the North American Vertical Datum of 1988 (NAVD 88). NAD 83, along with NAVD 88, is set to be replaced with a new GPS- and gravimetric geoid model-based geometric reference frame and geopotential datum, potentially Datum of 2022, in 2025. First North American Datum of 1901 In 1901 the United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Latitude And Longitude
A geographic coordinate system (GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on Earth as latitude and longitude. It is the simplest, oldest, and most widely used type 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] [Amazon] |
Albers Equal-area Conic Projection
Albers is a Dutch and Low German patronymic surname, meaning "Albert's son". Notable people with the surname include: ;Academics * Heinrich Albers-Schönberg (1865–1921), German gynecologist and radiologist * :de:Johann Abraham Albers (1772–1821), German physician * Johann Christian Albers (1795–1857), German physician and malacologist * :de:Johann Friedrich Hermann Albers (1805–1867), German physician and pathologist * Josef Albers (1888–1976), German artist, mathematician and educator * Susanne Albers (born 1965), German computer scientist ;Arts * Anni Albers (1899–1994), German-American textile artist and printmaker * Diana Albers, American comic book letterer * :de:Eef Albers (born 1951), Dutch guitarist * Hans Albers (1891–1960), German actor and singer * :de:Henk Albers (1927–1987), Dutch comics artist and illustrator * Henri Albers (1866–1926), born Johan Hendrik Albers, French operatic baritone of Dutch birth * Hubertus Albers, (born 1965), German come ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cartography
Cartography (; from , 'papyrus, sheet of paper, map'; and , 'write') is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can be modeled in ways that communicate spatial information effectively. The fundamental objectives of traditional cartography are to: * Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing. Traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. * Represent the terrain of the mapped object on flat media. This is the concern of map projections. * Eliminate the mapped object's characteristics that are irrelevant to the map's purpose. This is the concern of Cartographic generalization, generalization. * Reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization. * Orchestrate the elements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
