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
The Sierra Club is an environmental organization in the United States. It was founded on May 28, 1892, in San Francisco, California, by the Scottish-American preservationist John Muir, who became its first president; the Sierra Club operates in the United States. Traditionally associated with the progressive movement, the club was one of the first large-scale environmental preservation organizations in the world, engages in lobbying politicians to promote environmentalist policies. Recent focuses of the club include promoting sustainable energy, mitigating global warming, opposing the use of coal; the club is known for its political endorsements, which are sought after by candidates in local elections. The Sierra Club is organized on both a local level; the club is divided into large chapters representing large geographic areas, some of which have tens of thousands of members. These chapters are divided into regional groups, special interest sections and task forces. While much activity is coordinated at a local level, the Club is a unified organization.
In addition to political advocacy, the Sierra Club organizes outdoor recreation activities, has been a notable organization for mountaineering and rock climbing in the United States. Members of the Sierra Club pioneered the Yosemite Decimal System of climbing, were responsible for a substantial amount of the early development of climbing. Much of this activity occurred in the group's namesake Sierra Nevada; the Sierra Club does not set standards for or regulate alpinism, but it organizes wilderness courses and occasional alpine expeditions for members. In California, the club, through its outdoor recreation groups, is considered the state's analogue to other state mountaineering clubs such as Mazamas or the Colorado Mountain Club; the Sierra Club's stated mission is "To explore and protect the wild places of the earth. Each year, five directors are elected to three-year terms, all club members are eligible to vote. A president is elected annually by the Board from among its members; the Executive Director runs the day-to-day operations of the group.
Michael Brune of Rainforest Action Network, has served as the organization's executive director since 2010. Brune succeeded Carl Pope. Pope stepped down amid discontent. Sierra Club members belong to local groups. National and local special-interest sections and task forces address particular issues; the national Sierra Club sets overarching rules. The club is known for engaging in two main activities: promoting and guiding outdoor recreational activities, done throughout the United States but in California, political activism to promote environmental causes. Richard M. Skinner of the Brookings Institution describes the Sierra Club as one of the United States' "leading environmental organizations"; the Sierra Club makes endorsements of individual candidates for elected office, which has substantial weight given the club's reputation and large membership. Journalist Robert Underwood Johnson had worked with John Muir on the successful campaign to create a large Yosemite National Park surrounding the much smaller state park, created in 1864.
This campaign succeeded in 1890. As early as 1889, Johnson had encouraged Muir to form an "association" to help protect the Sierra Nevada, preliminary meetings were held to plan the group. Others involved in the early planning included artist William Keith, Willis Linn Jepson, Willard Drake Johnson, Joseph LeConte and David Starr Jordan. In May 1892, a group of professors from the University of California and Stanford University helped Muir and attorney Warren Olney launch the new organization modeled after the eastern Appalachian Mountain Club; the Sierra Club's charter members elected Muir president, an office he held until his death in 1914. The Club's first goals included establishing Glacier and Mount Rainier national parks, convincing the California legislature to give Yosemite Valley to the U. S. federal government, preserving California's coastal redwoods. Muir escorted President Theodore Roosevelt through Yosemite in 1903, two years the California legislature ceded Yosemite Valley and Mariposa Grove to the federal government.
The Sierra Club won its first lobbying victory with the creation of the country's second national park, after Yellowstone in 1872. In the first decade of the 1900s, the Sierra Club became embroiled in the Hetch Hetchy Reservoir controversy that divided preservationists from "resource management" conservationists. In the late 19th century, the city of San Francisco was outgrowing its limited water supply, which depended on intermittent local springs and streams. In 1890, San Francisco mayor James D. Phelan proposed to build a dam and aqueduct on the Tuolumne River, one of the largest southern Sierra rivers, as a way to increase and stabilize the city's water supply. Gifford Pinchot, a progressive supporter of public utilities and head of the US Forest Service, which had jurisdiction over the national parks, supported the creation of the Hetch
The Ventana Wilderness of Los Padres National Forest is a federally designated wilderness area located in the Santa Lucia Range along the Central Coast of California. This wilderness was established in 1969 when the Ventana Wilderness Act redesignated the 55,800-acre Ventana Primitive Area as the Ventana Wilderness and added land, totalling 98,000-acre. In 1978, the Endangered American Wilderness Act added 61,000 acres, increasing the total wilderness area to about 159,000 acres; the California Wilderness Act of 1984 added about 2,750 acres. The Los Padres Condor Range and River Protection Act of 1992 created the 14,500-acre Silver Peak Wilderness and added about 38,800 acres to the Ventana Wilderness in addition to designating the Big Sur River as a Wild and Scenic River. Most the Big Sur Wilderness and Conservation Act of 2002 expanded the wilderness for the fifth time, adding nearly 35,000 acres, increasing the total acreage of the wilderness to its present size of 240,026 acres; the Ventana Wilderness is named for the unique notch called "The Window" on a ridge near Ventana Double Cone.
According to local legend, this notch was once a natural stone arch. Three tribes of Native Americans — the Ohlone and Salinan — are believed to have been the first people to inhabit the area; the Ohlone known as the Costanoans, are believed to have lived in the region from San Francisco to Point Sur. The Esselen lived in the area between Point Sur south to Big Creek, inland, including the upper tributaries of the Carmel River and Arroyo Seco watersheds; the Salinan lived from Big Creek south to San Carpóforo Creek. Archaeological evidence shows that the Esselen lived in Big Sur as early as 3500 BC, leading a nomadic, hunter-gatherer existence; the indigenous people lived near the coast in winter, where they harvested rich stocks of mussels and other sea life. In the summer and fall they moved inland to harvest acorns gathered from the black oak, canyon live oak and tanbark oak on upper slopes in areas on the upper slopes of the steep canyons. U. S. Forest Service Chief Forester R. Y. Stuart ordered the Monterey Ranger District to establish the Ventana Primitive Area.
It consisted of 45,520 acres and was enlarged in 1937 to about 55,884 acres. When the U. S. Congress passed the Wilderness Act of 1964, the Ventana Primitive Area was formally designated as wilderness by law, rather than by a Forest Service regulation, which made the area's status subject to change at will; the Ventana Wilderness Area was formally established on August 18, 1969. The Ventana included 164,554 acres acres of extremely rugged terrain within the Santa Lucia Range of the Monterey Ranger District. In 1978, the Endangered American Wilderness Act added 61,000 acres, increasing the total wilderness area to about 159,000 acres; the California Wilderness Act of 1984 added about 2,750 acres. In 1992, the Los Padres Condor Range and River Protection Act created the 14,500-acre Silver Peak Wilderness and added about 38,800 acres to the Ventana Wilderness. In 2002, the Big Sur Wilderness and Conservation Act added nearly 35,000 acres, increasing the total acreage of the wilderness to its present size of 240,026 acres.
A small part, 736 acres, on the eastern edge of the wilderness is managed by the Bureau of Land Management. The topography of the Ventana Wilderness is characterized by steep-sided, sharp-crested ridges separating V-shaped youthful valleys. Most streams fall through narrow, vertical-walled canyons over bedrock or a veneer of boulders. Waterfalls, deep pools and thermal springs are found along major streams. Elevations range from 600 feet, where the Big Sur River leaves the Wilderness, to about 5,750 feet at the wilderness boundary near Junipero Serra Peak. Pico Blanco, which splits the north and south forks of the Little Sur River, was sacred in the native traditions of the Rumsien and the Esselen, who revered the mountain as a sacred place from which all life originated; the Spanish mission system led to the virtual destruction of the Indian population. Estimates for the pre-contact populations of most native groups in California have varied substantially. Alfred L. Kroeber suggests a 1770 population for the Esselen of 500.
Sherburne F. Cook raises this estimate to 750. A more recent calculation is that they numbered 1,185-1,285. Marked vegetation changes occur within the Wilderness, attributable to dramatic climatic and topographic variations coupled with an extensive fire history. Much of the Ventana Wilderness is covered by dense communities of chaparral, a group of fire-prone plant species, consisting of chamise and various species of manzanita and ceanothus. Other plant communities found in area include oak pine woodlands. Poison oak is found throughout the area. Deep narrow canyons cut by the fast moving Big Sur and Little Sur rivers support stands of coastal redwood, big leaf maple, sycamore. Small scattered stands of the rare, endemic bristlecone fir may be found on rocky slopes and canyon bottoms. Mountain lion, bear, deer and coyotes range the wilderness, as does the California condor, reintroduced to the region by the Ventana Wildlife Society. During the 1930s, the United States Civilian Conservation Corps constructed an extensive network of trails and trailheads that provided access to the Wilderness.
A number of these are no longer in use. The Pine Ridge
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
Spanish missions in California
The Spanish missions in California comprise a series of 21 religious outposts or missions established between 1769 and 1833 in today's U. S. State of California. Founded by Catholic priests of the Franciscan order to evangelize the Native Americans, the missions led to the creation of the New Spain province of Alta California and were part of the expansion of the Spanish Empire into the most northern and western parts of Spanish North America. Following long-term secular and religious policy of Spain in Spanish America, the missionaries forced the native Californians to live in settlements called reductions, disrupting their traditional way of life; the missionaries introduced European fruits, cattle, horses and technology. The missions have been accused by critics and now, of various abuses and oppression. In the end, the missions had mixed results in their objectives: to convert and transform the natives into Spanish colonial citizens. By 1810, Spain's king had been imprisoned by the French, financing for military payroll and missions in California ceased.
In 1821, Mexico achieved independence from Spain, although Mexico did not send a governor to California until 1824, only a portion of payroll was reinstated. The 21,000 Mission Indians produced hide and tallow and wool and textiles at this time, the leather products were exported to Boston, South America, Asia which sustained the colonial economy from 1810 until 1830, but tended to give British or New England merchant captains importance; the missions began to lose control over land in the 1820s, as unpaid military men unofficially encroached, but missions maintained authority over native neophytes and control of land holdings until the 1830s. At the peak of its development in 1832, the coastal mission system controlled an area equal to one-sixth of Alta California; the Alta California government secularized the missions after the passage of the Mexican secularization act of 1833. This divided the mission lands into land grants, in effect legitimizing and completing the transfer of Indian congregation lands to military commanders and their most loyal men.
The surviving mission buildings are the state's oldest structures and its most-visited historic monuments. They have become a symbol of California, appearing in many movies and television shows, are an inspiration for Mission Revival architecture; the oldest cities of California formed around or near Spanish missions, including the four largest: Los Angeles, San Diego, San Jose, San Francisco. Prior to 1754, grants of mission lands were made directly by the Spanish Crown. But, given the remote locations and the inherent difficulties in communicating with the territorial governments, power was transferred to the viceroys of New Spain to grant lands and establish missions in North America. Plans for the Alta California missions were laid out under the reign of King Charles III, came at least in part as a response to recent sightings of Russian fur traders along the California coast in the mid 1700s; the missions were to be interconnected by an overland route which became known as the Camino Real.
The detailed planning and direction of the missions was to be carried out by Friar Junípero Serra, O. F. M.. The Rev. Fermín Francisco de Lasuén took up Serra's work and established nine more mission sites, from 1786 through 1798. Work on the coastal mission chain was concluded in 1823, completed after Serra's death in 1784. Plans to build a twenty-second mission in Santa Rosa in 1827 were canceled; the Rev. Pedro Estévan Tápis proposed establishing a mission on one of the Channel Islands in the Pacific Ocean off San Pedro Harbor in 1784, with either Santa Catalina or Santa Cruz being the most locations, the reasoning being that an offshore mission might have attracted potential people to convert who were not living on the mainland, could have been an effective measure to restrict smuggling operations. Governor José Joaquín de Arrillaga approved the plan the following year, however an outbreak of sarampion killing some 200 Tongva people coupled with a scarcity of land for agriculture and potable water left the success of such a venture in doubt, so no effort to found an island mission was made.
In September 1821,the Rev. Mariano Payeras, "Comisario Prefecto" of the California missions, visited Cañada de Santa Ysabel east of Mission San Diego de Alcalá as part of a plan to establish an entire chain of inland missions; the Santa Ysabel Asistencia had been founded in 1818 as a "mother" mission, the plan's expanding beyond never came to fruition. In addition to the presidio and pueblo, the misión was one of the three major agencies employed by the Spanish sovereign to extend its borders and consolidate its colonial territories. Asistencias were small-scale missions that conducted Mass on days of obligation but lacked a resident priest; the Spanish Californians had never strayed from the coast. Each frontier station was forced to be self-supporting, as existing means of supply were inadequate to maintain a
Native Sons of the Golden West
The Native Sons of the Golden West is a fraternal service organization founded in 1875, limited to native born Californians and dedicated to historic preservation, documentation of historic structures and places in the state, the placement of historic plaques and other charitable functions within California. In 1890 they placed the first historical marker in the state to honor the discovery of gold which gave rise to the state nickname "Golden State" and "Golden West." Former U. S. President Richard M. Nixon and former Chief Justice of the United States Earl Warren were both past presidents of the NSGW; the Native Sons of the Golden West was founded 11 July 1875 by General A. M. Winn, a Virginian, as a lasting monument to the men and women of the Gold Rush Days. General Winn lived in California during the Gold Rush and was impressed with the spirit and perseverance of the "Forty-Niners." In speaking of his object in organizing the Order General Winn said "For twenty years my mind had been running on some lasting style of monument to mark and perpetuate the discovery of gold I could not think of anything that would not perish in course of time.
At last it came to my mind that an Order composed of native sons would effect the object and be sustained by pride of parentage and place of nativity while it would be an imperishable memento an institution that would last through all time." The chief objects of the Order as set forth in its constitution were, "To perpetuate in the minds of all native Californians the memories of the days of'49 to encourage a lively interest in all matters and measures relating to the promotion of the national interests and to the upbuilding of the State of California." Today, the Native Sons of the Golden West is open to membership from any native-born, current or former resident of California origin. The Native Sons of the Golden West is a fraternal organization. Organized locally into "Parlors," the group is best known for the large number of commemorative markers it has placed throughout the state, they have the Native Daughters of the Golden West. The term Golden West is a common colloquialism for California, popularly known as the Golden State.
The Native Sons began as an organization "embracing only the sons of those sturdy pioneers who arrived on this coast prior to the admission of California as a state." In the 1920s, the Native Sons took two different stances. In 1920, then-Grand President William P. Canbu of the Native Sons wrote that “California was given by God to a white people, with God’s strength we want to keep it as He gave it to us.” The Native Sons opposed Chinese and Japanese immigration and waged an unsuccessful legal battle for Japanese-Americans to be disenfranchised during World War II. However, by contrast, the Native Sons fought for California Native American rights. "The Commonwealth Club of San Francisco was looking into the matter of Indian rights under the 18 treaties as early as 1909. This resulted in a special section on Indian Affairs for the purpose of making a complete study of the rights and present condition of California Indians in 1924; the Native Sons was one of the groups, active in this area. Study committees were formed and publicity as to the needs of the California Indians appeared in its magazine, the California Grizzly Bear.
In 1922 and again in 1925, there were articles of real importance in arousing public opinion. In Nevada City, Native Sons Hydraulic Parlor No. 58 "aided the American Indians and succeeded in having the land set aside for native inhabitants. In April 1913, Indian agent C. H. Ashbury came from Reno to determine if the Indian land claims was valid and to conduct the proceedings, calling neighbors, city trustees, member of the Native Sons and Daughters to testify..."Today, the Native Sons welcome native Californians of all races. The current organization has many Asian Americans, Hispanic Americans and African American members, some of whom have served in the order's highest offices. Throughout its history, members of the Native Sons have safeguarded many of the landmarks of California's pioneer days and rehabilitating them and donating them to the State or local governments. Sutter's Fort, Sacramento: By 1888 the once proud fort built by John Sutter was abandoned and deteriorating and the City of Sacramento sought to demolish it.
C. E. Grunsky of Native Sons of the Golden West Sunset Parlor #26 in Sacramento led the fight to purchase and restore this most important symbol of California's pioneer history. After two years of fundraising, the Native Sons bought the historic Central Building and turned the land and building over to the State of California for further restoration. San Francisco Maritime National Historical Park, San Francisco: The Grace Quan is a reproduction of a 19th-century Chinese shrimp fishing junk; the replica was built in 2003 by the San Francisco Maritime National Historical Park and all of the wood for construction was donated by Native Sons, Redwood Parlor #66. Rancho Petaluma Adobe, Petaluma: In 1910, Native Sons of the Golden West, Petaluma Parlor #27 purchased what remained of General Mariano G. Vallejo's vast adobe ranch house. Over half of the building had succumbed to the forces of nature. In 1932 it was registered as California State Historical Landmark #18. After years of work and fundraising, the restored historic site was turned over to the State of California in 1951.
San Pasqual Battlefield State Historic Park, Escondido: San Pasqual Battlefield State Historic Park honors the soldiers who fought in the 1846 Battle of San Pasqual, the bloodiest battle in California during the Mexican–American War. The Native Sons of the Golden West were instrumental in raising
U.S. National Geodetic Survey
"United States Coast Survey" and "United States Coast and Geodetic Survey" redirect here. They are former scientific agencies of the United States government which should not be confused with the United States Coast Guard, a seagoing U. S. government law enforcement and safety agency, the modern Coast Survey, a U. S. government agency that makes nautical charts, or the United States Geological Survey, a U. S. government agency that studies earth science and makes topographical maps. The National Geodetic Survey the United States Survey of the Coast, United States Coast Survey, United States Coast and Geodetic Survey, is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication. Since its foundation in its present form in 1970, it has been part of the National Oceanic and Atmospheric Administration, of the United States Department of Commerce; the National Geodetic Survey's history and heritage are intertwined with those of other NOAA offices.
As the U. S. Coast Survey and U. S. Coast and Geodetic Survey, the agency operated a fleet of survey ships, from 1917 the Coast and Geodetic Survey was one of the uniformed services of the United States with its own corps of commissioned officers. Upon the creation of the Environmental Science Services Administration in 1965, the commissioned corps was separated from the Survey to become the Environmental Science Services Administration Corps. Upon the creation of NOAA in 1970, the ESSA Corps became the National Oceanic and Atmospheric Administration Commissioned Officer Corps. Thus, the National Geodetic Survey's ancestor organizations are the ancestors of today's NOAA Corps and Office of Coast Survey and are among the ancestors of today's NOAA fleet. In addition, today's National Institute of Standards and Technology, although long since separated from the Survey, got its start as the Survey's Office of Weights and Measures; the National Geodetic Survey is an office of NOAA's National Ocean Service.
Its core function is to maintain the National Spatial Reference System, "a consistent coordinate system that defines latitude, height, scale and orientation throughout the United States." NGS is responsible for defining the NSRS and its relationship with the International Terrestrial Reference Frame. The NSRS enables precise and accessible knowledge of where things are in the United States and its territories; the NSRS may be divided into its geometric and physical components. The official geodetic datum of the United States, NAD83 defines the geometric relationship between points within the United States in three-dimensional space; the datum may be accessed via NGS's network of survey marks or through the Continuously Operating Reference Station network of GPS reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF; the physical components of the NSRS are reflected in its height system, defined by the vertical datum NAVD88. This datum is a network of orthometric heights obtained through spirit leveling.
Because of the close relationship between height and Earth's gravity field, NGS collects and curates terrestrial gravity measurements and develops regional models of the geoid and its slope, the deflection of the vertical. NGS is responsible for ensuring the accuracy of the NSRS over time as the North American plate rotates and deforms over time due to crustal strain, post-glacial rebound, elastic deformation of the crust, other geophysical phenomena. NGS will release new datums in 2022; the North American Terrestrial Reference Frame of 2022 will supersede NAD83 in defining the geometric relationship between the North American plate and the ITRF. United States territories on the Pacific and Mariana plates will have their own respective geodetic datums; the North American-Pacific Geopotential Datum of 2022 will separately define the height system of the United States and its territories, replacing NAVD88. It will use a geoid model accurate to 1 centimeter to relate orthometric height to ellipsoidal height measured by GPS, eliminating the need for future leveling projects.
This geoid model will be based on airborne and terrestrial gravity measurements collected by NGS's GRAV-D program as well as satellite-based gravity models derived from observations collected by GRACE, GOCE, satellite altimetry missions. NGS provides a number of other public services, it maps changing shorelines in the United States and provides aerial imagery of regions affected by natural disasters, enabling rapid damage assessment by emergency managers and members of the public. The Online Positioning and User Service processes user-input GPS data and outputs position solutions within the NSRS; the agency offers other tools for conversion between datums. The original predecessor agency of the National Geodetic Survey was the United States Survey of the Coast, created within the United States Department of the Treasury by an Act of Congress on February 10, 1807, to conduct a "Survey of the Coast." The Survey of the Coast, the United States government's first scientific agency, represented the interest of the administration of President Thomas Jefferson in science and the stimulation of international trade by using scientific surveying methods to chart t