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Australian Height Datum
The Australian Height Datum was introduced in 1971 as the official vertical datum for Australia, and thereby serves as the benchmark to which all height measurements are referred. The Australian Height Datum is an amalgamation of decades of spirit levelling work conducted by numerous state and territory authorities across the country, and was corrected to align with the mean sea level observations of thirty tide gauges positioned around the entire coastline. While it remains the published vertical datum for all surveying and engineering operations performed throughout Australia, newer technologies have uncovered numerous deficiencies, offsets and distortions within the Australian Height Datum, leading to discussions about defining a new Australian vertical datum. Background The National Mapping Council (pre-1945) Prior to the creation of the Australian Height Datum, levelling surveys were carried out by professional surveyors for construction and mapping purposes using o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric System
The metric system is a system of measurement that succeeded the decimalised system based on the metre that had been introduced in France in the 1790s. The historical development of these systems culminated in the definition of the International System of Units (SI) in the mid-20th century, under the oversight of an international standards body. Adopting the metric system is known as ''metrication''. The historical evolution of metric systems has resulted in the recognition of several principles. Each of the fundamental dimensions of nature is expressed by a single base unit of measure. The definition of base units has increasingly been realised from natural principles, rather than by copies of physical artefacts. For quantities derived from the fundamental base units of the system, units derived from the base units are used—e.g., the square metre is the derived unit for area, a quantity derived from length. These derived units are coherent, which means that they inv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia (continent)
The continent of Australia, sometimes known in technical contexts by the names Sahul (), Australia-New Guinea, Australinea, Meganesia, or Papualand to distinguish it from the Australia, country of Australia, is located within the Southern Hemisphere, Southern and Eastern Hemisphere, Eastern hemispheres. The name "Sahul" takes its name from the Sahul Shelf, which is a part of the continental shelf of the Australian continent. The continent includes mainland Australia, Tasmania, the island of New Guinea (Papua New Guinea and Indonesian Western New Guinea), the Aru Islands Regency, Aru Islands, the Ashmore and Cartier Islands, most of the Coral Sea Islands, and some other list of islands of Australia, nearby islands. Situated in the geographical region of Oceania, Australia is the Continent#Area and population, smallest of the seven traditional continents. The continent includes a continental shelf overlain by shallow seas which divide it into several landmasses—the Arafura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Staff
{{short description, Graduated rod used to measure differences between heights A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a vertical datum. Rod construction and materials Levelling rods can be one piece, but many are sectional and can be shortened for storage and transport or lengthened for use. Aluminum rods may be shortened by telescoping sections inside each other, while wooden rod sections can be attached to each other with sliding connections or slip joints, or hinged to fold when not in use. There are many types of rods, with names that identify the form of the graduations and other characteristics. Markings can be in imperial or metric units. Some rods are graduated on one side only while others are marked on both sides. If marked on both sides, the markings can be identical or can have imperial units on one side and metr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fore Sight (surveying)
This is a glossary of levelling terms. Levelling is a surveying method used to find relative height, one use of which is to ensure ground is level during construction, for example, when excavating to prepare for laying a foundation for a house. Levelling terms * Automatic level – variant of the dumpy level, that makes use of a compensator that ensures that the line of sight remains horizontal once the operator has roughly leveled the instrument. The surveyor sets the instrument up quickly and doesn't have to relevel it carefully each time he sights on a rod on another point. It also reduces the effect of minor settling of the tripod. Three adjustment screws are used to level the instrument. * Back sight (BS) – short for "back sight reading", the first staff reading taken by the surveyor after the levelling instrument is set up and levelled. B.S is generally taken on the point of known reduced level as on the benchmark or a change point. * Benchmark (surveying) – fix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back Sight
This is a glossary of levelling terms. Levelling is a surveying method used to find relative height, one use of which is to ensure ground is level during construction, for example, when excavating to prepare for laying a foundation for a house. Levelling terms * Automatic level – variant of the dumpy level, that makes use of a compensator that ensures that the line of sight remains horizontal once the operator has roughly leveled the instrument. The surveyor sets the instrument up quickly and doesn't have to relevel it carefully each time he sights on a rod on another point. It also reduces the effect of minor settling of the tripod. Three adjustment screws are used to level the instrument. * Back sight (BS) – short for "back sight reading", the first staff reading taken by the surveyor after the levelling instrument is set up and levelled. B.S is generally taken on the point of known reduced level as on the benchmark or a change point. * Benchmark (surveying) – fixe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Squares Adjustment
Least-squares adjustment is a model for the solution of an overdetermined system of equations based on the principle of least squares of observation residuals. It is used extensively in the disciplines of surveying, geodesy, and photogrammetry—the field of geomatics, collectively. Formulation There are three forms of least squares adjustment: ''parametric'', ''conditional'', and ''combined'': * In parametric adjustment, one can find an observation equation ''h(X)=Y'' relating observations ''Y'' explicitly in terms of parameters ''X'' (leading to the A-model below). * In conditional adjustment, there exists a condition equation which is ''g(Y)=0'' involving only observations ''Y'' (leading to the B-model below) — with no parameters ''X'' at all. * Finally, in a combined adjustment, both parameters ''X'' and observations ''Y'' are involved implicitly in a mixed-model equation ''f(X,Y)=0''. Clearly, parametric and conditional adjustments correspond to the more general combined case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Levelling Terms
This is a glossary of levelling terms. Levelling is a surveying method used to find relative height, one use of which is to ensure ground is level during construction, for example, when excavating to prepare for laying a foundation for a house. Levelling terms * Automatic level – variant of the dumpy level, that makes use of a compensator that ensures that the line of sight remains horizontal once the operator has roughly leveled the instrument. The surveyor sets the instrument up quickly and doesn't have to relevel it carefully each time he sights on a rod on another point. It also reduces the effect of minor settling of the tripod. Three adjustment screws are used to level the instrument. * Back sight (BS) – short for "back sight reading", the first staff reading taken by the surveyor after the levelling instrument is set up and levelled. B.S is generally taken on the point of known reduced level as on the benchmark or a change point. * Benchmark (surveying) – fixed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coast
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor important ecosystems such as freshwater or estuarine wetlands, which are important for bird populations and other terrestrial animals. In wave-protected areas they harbor saltmarshes, mangroves or seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic species. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals (e.g. mussels, starfish, barnacles) and various kinds of seaweeds. Along tropical coasts with clear, nutrient-poor water, coral reefs can often be found between depths of . According to a United Nations atlas, 44% of all people live within 5 km ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Government
The Australian Government, also known as the Commonwealth Government, is the national government of Australia, a federal parliamentary constitutional monarchy. Like other Westminster-style systems of government, the Australian Government is made up of three branches: the executive (the prime minister, the ministers, and government departments), the legislative (the Parliament of Australia), and the judicial. The legislative branch, the federal Parliament, is made up of two chambers: the House of Representatives (lower house) and Senate (upper house). The House of Representatives has 151 members, each representing an individual electoral district of about 165,000 people. The Senate has 76 members: twelve from each of the six states and two each from Australia's internal territories, the Australian Capital Territory and Northern Territory. The Australian monarch, currently King Charles III, is represented by the governor-general. The Australian Government in its executi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queensland
) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_date = Colony of Queensland , established_title2 = Separation from New South Wales , established_date2 = 6 June 1859 , established_title3 = Federation , established_date3 = 1 January 1901 , named_for = Queen Victoria , demonym = , capital = Brisbane , largest_city = capital , coordinates = , admin_center_type = Administration , admin_center = 77 local government areas , leader_title1 = Monarch , leader_name1 = Charles III , leader_title2 = Governor , leader_name2 = Jeannette Young , leader_title3 = Premier , leader_name3 = Annastacia Palaszczuk ( ALP) , legislature = Parliament of Queensland , judiciary = Supreme Court of Queensland , national_representation = Parliament of Australia , national_representation_t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Territory
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west ( 129th meridian east), South Australia to the south ( 26th parallel south), and Queensland to the east ( 138th meridian east). To the north, the territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and other islands of the Indonesian archipelago. The NT covers , making it the third-largest Australian federal division, and the 11th-largest country subdivision in the world. It is sparsely populated, with a population of only 249,000 – fewer than half as many people as in Tasmania. The largest population center is the capital city of Darwin. The archaeological history of the Northern Territory may have begun more than 60,000 years ago when humans first sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Australian Survey Corps
The Royal Australian Survey Corps (RA Svy) was a Corps of the Australian Army, formed on 1 July 1915 and disbanded on 1 July 1996. As one of the principal military survey units in Australia, the role of the Royal Australian Survey Corps was to provide the maps, aeronautical charts, hydrographical charts and geodetic and control survey data required for land combat operations. Functional responsibilities associated with this role were: theatre wide geodetic survey for – artillery, naval gunfire and close air support – mapping and charting – navigation systems – command and control, communications, intelligence, reconnaissance and surveillance systems; map production and printing for new maps and charts, plans, overprints, battle maps, air photo mosaics and photomaps, rapid map and chart revision; map holding and map distribution; production, maintenance and distribution of digital topographic information and products. RA Svy survey and mapping information was, and still is, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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