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Philadelphia Rod
A Philadelphia rod is a level staff used in surveying. The rod is used in levelling procedures to determine elevations and is read using a level. A Philadelphia rod consists of two sliding sections graduated in hundredths of a foot. On the front of the rod the graduation increasing from zero at the bottom. On the back of the rod the graduation decrease from 13.09 ft at the bottom to 7 ft. The division of the device in two sliding sections are devised for ease of transport. Readings of or less, and up to , can be measured. It has a rear section that slides on the front section. The rod must be fully extended, when higher measurements are needed to avoid reading errors. Distances of up to may be read. File:Reading Leveling Rod jpeg.png, Reading a Philadelphia rod File:Leveling Rod reading examples jpeg.png, Philadelphia rod reading examples The rod may be equipped with a target to increase the readable range of the rod. When the target is equipped with a Vernier scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Staff
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. When used for stadiametric rangefinding, the level staff is called a stadia rod. 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 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surveying
Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geometry), points and the Euclidean distance, distances and angles between them. These points are usually on the surface of the Earth, and they are often used to establish maps and boundaries for ownership, locations, such as the designated positions of structural components for construction or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales. A professional in land surveying is called a land surveyor. Surveyors work with elements of geodesy, geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages, and the law. They use equipment, such as total stations, robotic total stations, theodolites, Satellite navigation, GNSS receivers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levelling
Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum. It is widely used in geodesy and cartography to measure vertical position with respect to a vertical datum, and in construction to measure height differences of construction artifacts. In photolithography, the same term is used in a lithography machine calibration step measuring or calibrating wafer surface height with respect to a reference. Optical levelling Optical levelling, also known as spirit levelling and differential levelling, employs an '' optical level'', which consists of a precision telescope with crosshairs and stadia marks. The cross hairs are used to establish the level point on the target, and the stadia allow range-finding; stadia are usually at ratios of 100:1, in which case one metre between the stadia marks on the '' level staff'' (or ''rod'') represents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elevation
The elevation of a geographic location (geography), ''location'' is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational equipotential surface, surface (see Geodetic datum#Vertical datum, Geodetic datum ยง Vertical datum). The term ''elevation'' is mainly used when referring to points on the Earth's surface, while ''altitude'' or ''geopotential height'' is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, and ''three-dimensional space, depth'' is used for points below the surface. Elevation is not to be confused with the distance from the center of the Earth. Due to the equatorial bulge, the summits of Mount Everest and Chimborazo (volcano), Chimborazo have, respectively, the largest elevation and the largest ECEF, geocentric distance. Aviation In aviation, the term ''elevation'' or ''aerodrome elevation'' is defined by the IC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumpy Level
A level is an optical instrument used to establish or verify points in the same horizontal plane in a process known as '' levelling''. It is used in conjunction with a levelling staff to establish the relative height or levels (the vertical separation) of objects or marks. It is widely used in surveying and construction to measure height differences and to transfer, measure, and set heights of known objects or marks. It is also known as a surveyor's level, builder's level, dumpy level or the historic "Y" level. It operates on the principle of establishing a visual level relationship between two or more points, for which an inbuilt optical telescope and a highly accurate bubble level are used to achieve the necessary accuracy. Traditionally the instrument was completely adjusted manually to ensure a level line of sight, but modern automatic versions self-compensate for slight errors in the coarse levelling of the instrument, and are thereby quicker to use. The optical level sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernier Scale
A vernier scale ( ), named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, which increases resolution and reduces measurement uncertainty by using vernier acuity. It may be found on many types of instrument measuring length or measuring angles, but in particular on a vernier caliper, which measures lengths of human-scale objects (including internal and external diameters). The vernier is a subsidiary scale replacing a single measured-value pointer, and has for instance ten divisions equal in distance to nine divisions on the main scale. The interpolated reading is obtained by observing which of the vernier scale graduations is coincident with a graduation on the main scale, which is easier to perceive than visual estimation between two points. Such an arrangement can go to a higher resolution by using a higher scale ratio, known as the vernier constant. A ver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guilford, Connecticut
Guilford is a town in New Haven County, Connecticut, United States, that borders Madison, Connecticut, Madison, Branford, Connecticut, Branford, North Branford, Connecticut, North Branford and Durham, Connecticut, Durham, and is situated on Interstate 95 in Connecticut, I-95 and the Connecticut coast. The town is part of the South Central Connecticut Planning Region, Connecticut, South Central Connecticut Planning Region. The population was 22,073 at the 2020 United States census, 2020 census. History Prior to European European colonization of the Americas, colonization, the area that became Guilford was the site of Menunkatuck, a Quinnipiac village. The Quinnipiac spoke Quiripi language, Quiripi, one of the Eastern Algonquian languages, Eastern Algonquian branches of the Algonquian languages, Algonquian language family. By 1614, the Dutch had surveyed, charted, and established New Netherland, a colonial province, with claimed territories from the Delmarva Peninsula to Cape Cod. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
