United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, the natural hazards that threaten it; the organization has four major science disciplines, concerning biology, geography and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility; the USGS is a bureau of the United States Department of the Interior. The USGS employs 8,670 people and is headquartered in Reston, Virginia; the USGS has major offices near Lakewood, Colorado, at the Denver Federal Center, Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world." The agency's previous slogan, adopted on the occasion of its hundredth anniversary, was "Earth Science in the Public Service." Since 2012, the USGS science focus is directed at six topical "Mission Areas", namely Climate and Land Use Change, Core Science Systems, Ecosystems and Minerals and Environmental Health, Natural Hazards, Water.
In December 2012, the USGS split the Energy and Minerals and Environmental Health Mission Area resulting in seven topical Mission Areas, with the two new areas being: Energy and Minerals and Environmental Health. Administratively, it is divided into six Regional Units. Other specific programs include: Earthquake Hazards Program monitors earthquake activity worldwide; the National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location and magnitude of global earthquakes. The USGS runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System; the USGS informs authorities, emergency responders, the media, the public, both domestic and worldwide, about significant earthquakes. It maintains long-term archives of earthquake data for scientific and engineering research, it conducts and supports research on long-term seismic hazards. USGS has released the UCERF California earthquake forecast.
As of 2005, the agency is working to create a National Volcano Early Warning System by improving the instrumentation monitoring the 169 volcanoes in U. S. territory and by establishing methods for measuring the relative threats posed at each site. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time; the USGS collaborates with Canadian and Mexican government scientists, along with the Commission for Environmental Cooperation, to produce the North American Environmental Atlas, used to depict and track environmental issues for a continental perspective. The USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online. National Climate Change and Wildlife Science Center implements partner-driven science to improve understanding of past and present land use change, develops relevant climate and land use forecasts, identifies lands and communities that are most vulnerable to adverse impacts of change from the local to global scale.
Since 1962, the Astrogeology Research Program has been involved in global and planetary exploration and mapping. In collaboration with Stanford University, the USGS operates the USGS-Stanford Ion Microprobe Laboratory, a world-class analytical facility for U--Pb geochronology and trace element analyses of minerals and other earth materials. USGS operates a number of water related programs, notably the National Streamflow Information Program and National Water-Quality Assessment Program. USGS Water data is publicly available from their National Water Information System database; the USGS operates the National Wildlife Health Center, whose mission is "to serve the nation and its natural resources by providing sound science and technical support, to disseminate information to promote science-based decisions affecting wildlife and ecosystem health. The NWHC provides information, technical assistance, research and leadership on national and international wildlife health issues." It is the agency responsible for surveillance of H5N1 avian influenza outbreaks in the United States.
The USGS runs 17 biological research centers in the United States, including the Patuxent Wildlife Research Center. The USGS is investigating collaboration with the social networking site Twitter to allow for more rapid construction of ShakeMaps; the USGS produces several national series of topographic maps which vary in scale and extent, with some wide gaps in coverage, notably the complete absence of 1:50,000 scale topographic maps or their equivalent. The largest and best-known topographic series is the 7.5-minute, 1:24,000 scale, quadrangle, a non-metric scale unique to the United States. Each of these maps covers an area bounded by two lines of latitude and two lines of longitude spaced 7.5 minutes apart. Nearly 57,000 individual maps in this series cover the 48 contiguous states, Hawaii, U. S. territories, areas of Alaska near Anchorage and Prudhoe Bay. The area covered by each map varies with the latitude of its represented location due to convergence of the meridians. At lower latitudes, near 30° north, a 7.5-minute quadrangle contains an area of about 64 square miles.
At 49° north latitude, 49 square miles are contained within a quadrangle of that size. As a unique non-metric map scale, the 1:24,000 scale requires a separate and specialized romer scale for pl
Mauna Kea is a dormant volcano on the island of Hawaii. Its peak is 4,207.3 m above sea level. Most of the mountain is under water, when measured from its oceanic base, Mauna Kea is the tallest mountain in the world measuring over 10,000 m. Mauna Kea is about a million years old, has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous. Late volcanism has given it a much rougher appearance than its neighboring volcanoes due to construction of cinder cones, decentralization of its rift zones, glaciation on its peak, weathering by the prevailing trade winds. Mauna Kea last is now considered dormant; the peak is about 38 m higher than its more massive neighbor. In Hawaiian mythology, the peaks of the island of Hawaii are sacred. An ancient law allowed only high-ranking aliʻi to visit its peak. Ancient Hawaiians living on the slopes of Mauna Kea relied on its extensive forests for food, quarried the dense volcano-glacial basalts on its flanks for tool production.
When Europeans arrived in the late 18th century, settlers introduced cattle and game animals, many of which became feral and began to damage the mountain's ecological balance. Mauna Kea can be ecologically divided into three sections: an alpine climate at its summit, a Sophora chrysophylla–Myoporum sandwicense forest on its flanks, an Acacia koa–Metrosideros polymorpha forest, now cleared by the former sugar industry, at its base. In recent years, concern over the vulnerability of the native species has led to court cases that have forced the Hawai'i Department of Land and Natural Resources to eradicate all feral species on the mountain. With its high elevation, dry environment, stable airflow, Mauna Kea's summit is one of the best sites in the world for astronomical observation. Since the creation of an access road in 1964, thirteen telescopes funded by eleven countries have been constructed at the summit; the Mauna Kea Observatories are used for scientific research across the electromagnetic spectrum and comprise the largest such facility in the world.
Their construction on a landscape considered sacred by Native Hawaiians continues to be a topic of debate. Mauna Kea is one of five volcanoes that form the island of Hawaii, the largest and youngest island of the Hawaiian–Emperor seamount chain. Of these five hotspot volcanoes, Mauna Kea is the fourth oldest and fourth most active, it began as a preshield volcano driven by the Hawaii hotspot around one million years ago, became exceptionally active during its shield stage until 500,000 years ago. Mauna Kea entered its quieter post-shield stage 250,000 to 200,000 years ago, is dormant. Mauna Kea does not have a visible summit caldera, but contains a number of small cinder and pumice cones near its summit. A former summit caldera may have been filled and buried by summit eruption deposits. Mauna Kea is over 32,000 km3 in volume, so massive that it and its neighbor, Mauna Loa, depress the ocean crust beneath it by 6 km; the volcano continues to slip and flatten under its own weight at a rate of less than 0.2 mm per year.
Much of its mass lies east of its present summit. Mauna Kea stands 4,207.3 m above sea level, about 38 m higher than its neighbor Mauna Loa, is the highest point in the state of Hawaii. Measured from its base on the ocean floor, it rises over 10,000 m greater than the elevation of Mount Everest above sea level. Like all Hawaiian volcanoes, Mauna Kea has been created as the Pacific tectonic plate has moved over the Hawaiian hotspot in the Earth's underlying mantle; the Hawaii island volcanoes are the most recent evidence of this process that, over 70 million years, has created the 6,000 km -long Hawaiian Ridge–Emperor seamount chain. The prevailing, though not settled, view is that the hotspot has been stationary within the planet's mantle for much, if not all of the Cenozoic Era. However, while Hawaiian volcanism is well understood and extensively studied, there remains no definite explanation of the mechanism that causes the hotspot effect. Lava flows from Mauna Kea overlapped in complex layers with those of its neighbors during its growth.
Most prominently, Mauna Kea is built upon older flows from Kohala to the northwest, intersects the base of Mauna Loa to the south. The original eruptive fissures in the flanks of Mauna Kea were buried by its post-shield volcanism. Hilo Ridge, a prominent underwater rift zone structure east of Mauna Kea, was once believed to be a part of the volcano; the shield-stage lavas that built the enormous main mass of the mountain are tholeiitic basalts, like those of Mauna Loa, created through the mixing of primary magma and subducted oceanic crust. They are covered by the oldest exposed rock strata on Mauna Kea, the post-shield alkali basalts of the Hāmākua Volcanics, which erupted between 250,000 and 70–65,000 years ago; the most recent volcanic flows are hawaiites and mugearites: they are the post-shield Laupāhoehoe Volcanics, erupted between 65,000 and 4,000 years ago. These changes in lava composition accompanied the slow reduction of the supply of magma to the summit, which led to weaker eruptions that gave way to isolated episodes associated with volcanic dormancy.
The Laupāhoehoe lavas are more viscous and contain more volatiles than the earlier tholeiitic basalts.
Denali is the highest mountain peak in North America, with a summit elevation of 20,310 feet above sea level. With a topographic prominence of 20,156 feet and a topographic isolation of 4,629 miles, Denali is the third most prominent and third most isolated peak on Earth, after Mount Everest and Aconcagua. Located in the Alaska Range in the interior of the U. S. state of Alaska, Denali is the centerpiece of Preserve. The Koyukon people who inhabit the area around the mountain have referred to the peak as "Denali" for centuries. In 1896, a gold prospector named it "Mount McKinley" in support of then-presidential candidate William McKinley. In August 2015, following the 1975 lead of the State of Alaska, the United States Department of the Interior announced the change of the official name of the mountain to Denali. In 1903, James Wickersham recorded the first attempt at climbing Denali, unsuccessful. In 1906, Frederick Cook claimed the first ascent, proven to be false; the first verifiable ascent to Denali's summit was achieved on June 7, 1913, by climbers Hudson Stuck, Harry Karstens, Walter Harper, Robert Tatum, who went by the South Summit.
In 1951, Bradford Washburn pioneered the West Buttress route, considered to be the safest and easiest route, therefore the most popular in use. On September 2, 2015, the U. S. Geological Survey announced that the mountain is 20,310 feet high, not 20,320 feet, as measured in 1952 using photogrammetry. Denali is a granitic pluton lifted by tectonic pressure from the subduction of the Pacific Plate beneath the North American Plate; the forces that lifted Denali cause many deep earthquakes in Alaska and the Aleutian Islands. The Pacific Plate is seismically active beneath Denali, a tectonic region, known as the "McKinley cluster". Denali has a summit elevation of 20,310 feet above sea level, making it the highest peak in North America and the northernmost mountain above 6,000 meters elevation in the world. Measured from base to peak at some 18,000 ft, it is among the largest mountains situated above sea level. Denali rises from a sloping plain with elevations from 1,000 to 3,000 ft, for a base-to-peak height of 17,000 to 19,000 ft.
By comparison, Mount Everest rises from the Tibetan Plateau at a much higher base elevation. Base elevations for Everest range from 13,800 ft on the south side to 17,100 ft on the Tibetan Plateau, for a base-to-peak height in the range of 12,000 to 15,300 ft. Denali's base-to-peak height is little more than half the 33,500 ft of the volcano Mauna Kea, which lies under water. Denali has two significant summits: the South Summit is the higher one, while the North Summit has an elevation of 19,470 ft and a prominence of 1,270 ft; the North Summit is sometimes counted as sometimes not. Five large glaciers flow off the slopes of the mountain; the Peters Glacier lies on the northwest side of the massif, while the Muldrow Glacier falls from its northeast slopes. Just to the east of the Muldrow, abutting the eastern side of the massif, is the Traleika Glacier; the Ruth Glacier lies to the southeast of the mountain, the Kahiltna Glacier leads up to the southwest side of the mountain. With a length of 44 mi, the Kahiltna Glacier is the longest glacier in the Alaska Range.
The Koyukon Athabaskans who inhabit the area around the mountain have for centuries referred to the peak as Dinale or Denali. The name is based on a Koyukon word for "high" or "tall". During the Russian ownership of Alaska, the common name for the mountain was Bolshaya Gora, the Russian translation of Denali, it was called Densmore's Mountain in the late 1880s and early 1890s after Frank Densmore, an Alaskan prospector, the first European to reach the base of the mountain. In 1896, a gold prospector named it McKinley as political support for then-presidential candidate William McKinley, who became president the following year; the United States formally recognized the name Mount McKinley after President Wilson signed the Mount McKinley National Park Act of February 26, 1917. In 1965, Lyndon B. Johnson declared the north and south peaks of the mountain the "Churchill Peaks", in honor of British statesman Winston Churchill; the Alaska Board of Geographic Names changed the name of the mountain to Denali in 1975, how it is called locally.
However, a request in 1975 from the Alaska state legislature to the United States Board on Geographic Names to do the same at the federal level was blocked by Ohio congressman Ralph Regula, whose district included McKinley's hometown of Canton. On August 30, 2015, just ahead of a presidential visit to Alaska, the Barack Obama administration announced the name Denali would be restored in line with the Alaska Geographic Board's designation. U. S. Secretary of the Interior Sally Jewell issued the order changing the name to Denali on August 28, 2015, effective immediately. Jewell said the change had been "a long time coming"; the renaming of the mountain received praise from Alaska's senior U. S. senator, Lisa Murkowski, who had introduced legislation to accomplish the name change, but it drew criticism from several politicians from Pres
Wrangell–St. Elias National Park and Preserve
Wrangell–St. Elias National Park and Preserve is an American national park and preserve managed by the National Park Service in south central Alaska; the park and preserve were established in 1980 by the Alaska National Interest Lands Conservation Act. The protected areas are included in an International Biosphere Reserve and are part of the Kluane/Wrangell–St. Elias/Glacier Bay/Tatshenshini-Alsek UNESCO World Heritage Site; the park and preserve form the largest area managed by the National Park Service with a total of 13,175,799 acres, an expanse that could encapsulate a total of six Yellowstone National Parks. The park includes a large portion of the Saint Elias Mountains, which include most of the highest peaks in the United States and Canada, yet are within 10 miles of tidewater, one of the highest reliefs in the world. Wrangell–St. Elias borders on Canada's Kluane National Park and Reserve to the east and approaches another American national park to the south, Glacier Bay; the chief distinction between park and preserve lands is that sport hunting is prohibited in the park and permitted in the preserve.
In addition, 9,078,675 acres of the park are designated as the largest single wilderness in the United States. Wrangell–St. Elias National Monument was designated on December 1, 1978, by President Jimmy Carter using the Antiquities Act, pending final legislation to resolve the allotment of public lands in Alaska. Establishment as a national park and preserve followed the passage of the Alaska National Interest Lands Conservation Act in 1980; the park has long cold winters and a short summer season. Plate tectonics are responsible for the uplift of the mountain ranges; the park's extreme high point is Mount Saint Elias at 18,008 feet, the second tallest mountain in both the United States and Canada. The park has been shaped by the competing forces of glaciation. Mount Wrangell is one of several volcanoes in the western Wrangell Mountains. In the St. Elias Range, Mount Churchill has erupted explosively within the past 2,000 years; the park's glacial features include Malaspina Glacier, the largest piedmont glacier in North America, Hubbard Glacier, the longest tidewater glacier in Alaska, Nabesna Glacier, the world's longest valley glacier.
The Bagley Icefield covers much of the park's interior, which includes 60% of the permanently ice-covered terrain in Alaska. At the center of the park, the boomtown of Kennecott exploited one of the world's richest deposits of copper from 1903 to 1938, exposed by and in part incorporated into Kennicott Glacier; the abandoned mine buildings and mills comprise a National Historic Landmark district. Wrangell–St. Elias National Park and Preserve includes the entire Wrangell range, the western portion of the Saint Elias Mountains and the eastern portion of the Chugach Mountains. Lesser ranges in the park or preserve include the Nutzotin Mountains, which are an extension of the Alaska Range, the Granite Range and the Robinson Mountains. Broad rivers run in glacial valleys between the ranges, including the Chitina River, Chisana River and the Nabesna River. All but the Chisana and Nabesna are tributaries to the Copper River, which flows along the western margin of the park and which has its headwaters within the park, at the Copper Glacier.
The park includes dozens of icefields. The Bagley Icefield covers portions of the St. Elias and Chugach ranges, Malaspina Glacier covers most of the southeastern extension of the park, with Hubbard Glacier at the park's extreme eastern boundary, the largest tidewater glacier in North America; the eastern boundary of the park is Alaska's border with Canada, where it is adjoined by Kluane National Park and Reserve. On the southeast the park is bounded by Tongass National Forest and the Gulf of Alaska; the remainder of the southern boundary follows the crest of the Chugach Mountains, adjoining Chugach National Forest. The western boundary is the Copper River, the northern boundary follows the Mentasta Mountains and borders Tetlin National Wildlife Refuge. Mount St. Elias is the second highest mountain in the United States. In total nine of the 16 highest peaks on U. S. soil are located in the park, along with North America's largest subpolar icefield, rivers, an active volcano, the historic Kennecott copper mines.
Both the St. Elias and Wrangell ranges have seen volcanic activity; the St. Elias volcanoes are considered extinct, but some of the volcanoes of the Wrangell Range have been active in Holocene time. Ten separate volcanoes have been documented in the western Wrangell Range, of which Mount Blackburn is the highest and Mount Wrangell is the most active. Mount St. Elias is situated on the border of Wrangell–St. Elias National Park and Kluane National Park and Reserve. At 18,074 feet,Nearly 66 percent of park and preserve land is designated as wilderness. Wrangell–St. Elias Wilderness is the largest designated wilderness in the United States; the park region is divided between national park lands, which only allow subsistence hunting by local rural residents, preserve lands, which allow sport hunting by the general public. Preserve lands include the Chitina valley north of the river, two parts of the Copper River valley east of the river, most of the Chisana and Nabesna valleys, lands along Yakutat Bay.
The park is accessible by highway from Anchorage. Chartered aircraft fly into the park. Wrangell–St. Elias received 79,450 visitors in 2018; the park area includes a few small settlements. Nabesna and Chisana are in the nort
In rock climbing and other climbing disciplines, climbers give a grade to a climbing route or boulder problem, intended to describe concisely the difficulty and danger of climbing it. Different types of climbing each have their own grading systems, many nationalities developed their own, distinctive grading systems. There are a number of factors that contribute to the difficulty of a climb, including the technical difficulty of the moves, the strength and level of commitment required, the difficulty of protecting the climber. Different grading systems consider these factors in different ways, so no two grading systems have an exact one-to-one correspondence. Climbing grades are inherently subjective, they may be the opinion of one or a few climbers the first ascensionist or the author of a guidebook. A grade for an individual route may be a consensus reached by many climbers who have climbed the route. While grades are applied consistently across a climbing area, there are perceived differences between grading at different climbing areas.
Because of these variables, a given climber might find a route to be either easier or more difficult than expected for the grade applied. In 1894, the Austrian mountaineer Fritz Benesch introduced the first known grading system for rock climbing; the Benesch scale had seven levels of difficulty, with level VII the easiest and level I the most difficult. Soon more difficult climbs were made, which were graded level 0 and 00. In 1923, the German mountaineer Willo Welzenbach compressed the scale and turned the order around, so that level 00 became level IV–V; this "Welzenbach scale" was adopted in 1935 by French mountaineers like Lucien Devies, Pierre Allain and Armand Charlet for routes in the Western Alps and in 1947 in Chamonix by the Union Internationale des Associations d'Alpinisme. It was renamed in 1968 as the UIAA scale. A 6-grade scale, it has been open-ended since 1979. For free climbing, there are many different grading systems varying according to country, they include: The Yosemite Decimal System of grading routes was developed as the Sierra Club grading system in the 1930s to rate hikes and climbs in the Sierra Nevada range.
The rock climbing portion was developed at Tahquitz Rock in southern California by members of the Rock Climbing Section of the Angeles Chapter of the Sierra Club in the 1950s. It spread to Canada and the rest of the Americas. A single-part classification system and protection rating categories were added later; the new classifications do not apply to every climb and usage varies widely. When a route involves aid climbing, its unique aid designation can be appended to the YDS free climbing rating. For example, the North America Wall on El Capitan would be classed "VI, 5.8, A5", or Medlicott Dome – Bachar/Yerian 5.11c The system consists of five classes indicating the technical difficulty of the hardest section. Class 1 is the easiest and consists of walking on terrain. Class 5 is climbing on vertical or near-vertical rock, requires skill and a rope to proceed safely. Un-roped falls would result in severe death. Class 6 was used to grade aid climbing. However, the separate A rating system became popular instead.
The original intention was that the classes would be subdivided decimally, so that a route graded 4.5 would be a scramble halfway between 4 and 5, 5.9 would be the hardest rock climb. Increased standards and improved equipment meant that climbs graded 5.9 in the 1960s are now only of moderate difficulty. Rather than regrade all climbs each time standards improve, additional grades were added at the top—originally only 5.10, but it soon became apparent that an open-ended system was needed, further grades of 5.11, 5.12, etc. were added, thus the system is no longer decimal. While the top grade was 5.10, a large range of climbs in this grade was completed, climbers realized a subdivision of the upper grades was required. Letter grades were added for climbs at 5.10 and above by adding a letter "a", "b", "c", or "d". The system considered only the technical difficulty of the hardest move on a route. For example, a route of 5.7 moves but with one 5.11b move would be graded 5.11b and a climb that consisted of 5.11b moves all along its route would be 5.11b.
Modern application of climbing grades on climbs at the upper end of the scale consider how sustained or strenuous a climb is, in addition to the difficulty of the single hardest move. The YDS system involves an optional Roman numeral grade that indicates the length and seriousness of the route; the Grade is more relevant to mountaineering and big wall climbing, not stated when talking about short rock climbs. The grades range from grade I to VI spanning a one-hour climb to a multi-day climb respectively. I–II: 1 or 2 pitches near the car, but may need to be avoided during avalanche season. III: Requires most of a day including the approach, which may require winter travel skills; the East Buttress route on Mt. Whitney is a grade III, yet it requires 1,000 feet of technical climbing and a total gain of over 6,000 vertical feet from trail head to summit. Only a minority of climbers, the most fit and seasoned, could do this route car to car in a day. Other grade III climbs, such as Cathedral Peak in Tuolumne, are done in one day.
IV: A multipitch route at higher altitude or remote location, which may involve multi-hour approaches in serious alpine terrain. A predawn start is indicated, unforeseen delays can le
In modern mapping, a topographic map is a type of map characterized by large-scale detail and quantitative representation of relief using contour lines, but using a variety of methods. Traditional definitions require a topographic map to show both man-made features. A topographic survey is published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of equal elevation. Natural Resources Canada provides this description of topographic maps:These maps depict in detail ground relief, forest cover, administrative areas, populated areas, transportation routes and facilities, other man-made features. Other authors define topographic maps by contrasting them with another type of map. However, in the vernacular and day to day world, the representation of relief is popularly held to define the genre, such that small-scale maps showing relief are called "topographic"; the study or discipline of topography is a much broader field of study, which takes into account all natural and man-made features of terrain.
Topographic maps are based on topographical surveys. Performed at large scales, these surveys are called topographical in the old sense of topography, showing a variety of elevations and landforms; this is in contrast to older cadastral surveys, which show property and governmental boundaries. The first multi-sheet topographic map series of an entire country, the Carte géométrique de la France, was completed in 1789; the Great Trigonometric Survey of India, started by the East India Company in 1802 taken over by the British Raj after 1857 was notable as a successful effort on a larger scale and for determining heights of Himalayan peaks from viewpoints over one hundred miles distant. Topographic surveys were prepared by the military to assist in planning for battle and for defensive emplacements; as such, elevation information was of vital importance. As they evolved, topographic map series became a national resource in modern nations in planning infrastructure and resource exploitation. In the United States, the national map-making function, shared by both the Army Corps of Engineers and the Department of the Interior migrated to the newly created United States Geological Survey in 1879, where it has remained since.1913 saw the beginning of the International Map of the World initiative, which set out to map all of Earth's significant land areas at a scale of 1:1 million, on about one thousand sheets, each covering four degrees latitude by six or more degrees longitude.
Excluding borders, each sheet was up to 66 cm wide. Although the project foundered, it left an indexing system that remains in use. By the 1980s, centralized printing of standardized topographic maps began to be superseded by databases of coordinates that could be used on computers by moderately skilled end users to view or print maps with arbitrary contents and scale. For example, the Federal government of the United States' TIGER initiative compiled interlinked databases of federal and local political borders and census enumeration areas, of roadways and water features with support for locating street addresses within street segments. TIGER was used in the 1990 and subsequent decennial censuses. Digital elevation models were compiled from topographic maps and stereographic interpretation of aerial photographs and from satellite photography and radar data. Since all these were government projects funded with taxes and not classified for national security reasons, the datasets were in the public domain and usable without fees or licensing.
TIGER and DEM datasets facilitated Geographic information systems and made the Global Positioning System much more useful by providing context around locations given by the technology as coordinates. Initial applications were professionalized forms such as innovative surveying instruments and agency-level GIS systems tended by experts. By the mid-1990s user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared; as of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt. Topographic maps have multiple uses in the present day: any type of geographic planning or large-scale architecture; the various features shown on the map are represented by conventional symbols. For example, colors can be used to indicate a classification of roads; these signs are explained in the margin of the map, or on a separately published characteristic sheet. Topographic maps are commonly called contour maps or topo maps.
In the United States, where the primary national series is organized by a strict 7.5-minute grid, they are called topo quads or quadrangles. Topographic maps conventionally show land contours, by means of contour lines. Contour lines are curves. In other words, every point on the marked line of 100 m elevation is 100 m above mean sea level; these maps show
A summit is a point on a surface, higher in elevation than all points adjacent to it. The topographic terms acme, apex and zenith are synonymous; the term top is used only for a mountain peak, located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are considered subsummits of the higher peak, are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may refer to the highest point along a line, trail, or route; the highest summit in the world is Everest with height of 8844.43 m above sea level. The first official ascent was made by Sir Edmund Hillary, they reached the mountain`s peak in 1953. Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective; the UIAA definition of a peak is.
Otherwise, it's a subpeak. In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit. A summit climbing differs from the common mountaineering. Summit expedition requires: 1+ year of training, a good physical shape, a special gear. Although a huge part of climber’s stuff can be left and taken at the base camps or given to porters, there is a long list of personal equipment. In addition to common mountaineers’ gear, Summit climbers need to take Diamox and bottles of oxygen. There are special requirements for crampons, ice axe, rappel device, etc. Geoid Hill – Landform that extends above the surrounding terrain Nadir Summit accordance Peak finder Summit Climbing Gear List