"kilometres). He underestimated this distance by 3.5%. The survey was a chain of quadrangles containing 33 triangles in all. Snell showed how planar formulae could be corrected to allow for the curvature of the earth. He also showed how to resection, or calculate, the position of a point inside a triangle using the angles cast between the vertices at the unknown point. These could be measured more accurately than bearings of the vertices, which depended on a compass. His work established the idea of surveying a primary network of control points, and locating subsidiary points inside the primary network later."
"Goniometer A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry is derived from two Greek words, """", meaning angle, and """", meaning measure. The first description of a goniometer, derived from the astrolabe, was apparently in 1538, by Gemma Frisius. Prior to the invention of the theodolite, the goniometer was used in surveying. The application of triangulation to geodesy was described in the second (1533) edition of ""Cosmograficus liber"" by Petri Appiani as a 16-page appendix by Frisius entitled ""Libellus de locorum describendorum ratione""."
"Goniometer A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry is derived from two Greek words, """", meaning angle, and """", meaning measure. The first description of a goniometer, derived from the astrolabe, was apparently in 1538, by Gemma Frisius. Prior to the invention of the theodolite, the goniometer was used in surveying. The application of triangulation to geodesy was described in the second (1533) edition of ""Cosmograficus liber"" by Petri Appiani as a 16-page appendix by Frisius entitled ""Libellus de locorum describendorum ratione""."
"Topographic Abney level An Abney level and clinometer, is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale. An internal mirror allows the user to see the bubble in the level while sighting a distant target. It can be used as a hand-held instrument or mounted on a Jacob's staff for more precise measurement, and it is small enough to carry in a coat pocket. The Abney level is an easy to use, relatively inexpensive, and, when used correctly, an accurate surveying"
"Goniometer (audio) A goniometer is often included in analog audio equipment to display a Lissajous figure which shows the amount of stereo (that is, phase differences) in a dual-channel signal. It allows the sound technician to adjust for optimal stereo and determine the makeup of errors such as an inverted signal. Many goniometers also provide a VU or PPM as a secondary function. A goniometer adapted for surround metering is called a 'jellyfish display'. This term was coined by DK-Technologies A/S from Denmark. Its function is to plot a signal on a two-dimensional area so that the correlation between the"
"Positioning goniometer A positioning goniometer or goniometric stage is a device used to rotate an object precisely (within a small angular range) about a fixed axis in space. Its appearance is similar to that of a linear stage. However, rather than moving linearly with respect to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. The distance of the center of rotation from the platform mounting surface is often chosen so that two different goniometer models may be stacked in an X-Y configuration and both stages will rotate about the same"
"malleolus of the fibula and a measurement will be taken using the degree scale on the circular portion of the tool. The only problem with goniometers is the accuracy of the reading is not always the greatest. Issues with the intra-measure (between measures) and inter-tester (between clinicians) reliability seem to increase as the experience of the examiner decreases. Some studies suggest that these errors can be anywhere between 5 and 10 degrees when completing repeated measures. These goniometers do come in different forms that some would argue will actually increase the reliability of the tool. The universal standard goniometer is"
"a plastic or metal tool with 1 degree increments. The arms usually are not longer than 12-inches so it can be hard to accurately pinpoint the exact landmark needed for measurement. A more reliable goniometer would be the telescopic-armed goniometer. There is a plastic circular axis as a classic goniometer but the arms extend out to as long as two feet in either direction. More recently in the twenty-first century, smartphone application developers have created mobile applications that are intended to perform like a goniometer. These applications (such as Knee Goniometer and Goniometer Pro) use the accelerometers in phones to"
"Gonioreflectometer A gonioreflectometer is a device for measuring a bidirectional reflectance distribution function (BRDF). The device consists of a light source illuminating the material to be measured and a sensor that captures light reflected from that material. The light source should be able to illuminate and the sensor should be able to capture data from a hemisphere around the target. The hemispherical rotation dimensions of the sensor and light source are the four dimensions of the BRDF. The 'gonio' part of the word refers to the device's ability to measure at different angles. Several similar devices have been built and"
"compare modern-day animal species, and to analyze the evolution of the human species in archaeology. Measurements of the skull based on specific anatomical reference points are used in both forensic facial reconstruction and portrait sculpture. Craniometry Craniometry is measurement of the cranium (the main part of the skull), usually the human cranium. It is a subset of cephalometry, measurement of the head, which in humans is a subset of anthropometry, measurement of the human body. It is distinct from phrenology, the pseudoscience that tried to link personality and character to head shape, and physiognomy, which tried the same for facial"
"and reflective which is the basis for the laser goniometer measurements. The laser goniometer can measure within a thousandth of a degree to specified or requested angles. Nanoindenter A nanoindenter is the main component for indentation hardness tests used in nanoindentation. Since the mid-1970s nanoindentation has become the primary method for measuring and testing very small volumes of mechanical properties. Nanoindentation, also called ""depth sensing indentation"" or ""instrumented indentation"", gained popularity with the development of machines that could record small load and displacement with high accuracy and precision. The load displacement data can be used to determine modulus of elasticity,"
"staff is only possible at short range, although it is possible to make special staffs that can be read at a distance without magnification. Abney levels remain in common use in several fields: Topographic Abney level An Abney level and clinometer, is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale. An internal mirror allows the user to see the bubble in the level while sighting a distant target. It can be used as a hand-held instrument or mounted on a Jacob's"
"point. Positioning goniometers typically use a worm drive with a partial worm wheel fixed to the underside of the stage platform meshing with a worm in the base. The worm may be rotated manually or by a motor as in automated positioning systems. Positioning goniometer A positioning goniometer or goniometric stage is a device used to rotate an object precisely (within a small angular range) about a fixed axis in space. Its appearance is similar to that of a linear stage. However, rather than moving linearly with respect to its base, the stage platform rotates partially about a fixed axis"
"a camera focused on the crystal. The most common type of goniometer is the ""kappa goniometer"", which offers three angles of rotation: the ω angle, which rotates about an axis perpendicular to the beam; the κ angle, about an axis at ~50° to the ω axis; and, finally, the φ angle about the loop/capillary axis. When the κ angle is zero, the ω and φ axes are aligned. The κ rotation allows for convenient mounting of the crystal, since the arm in which the crystal is mounted may be swung out towards the crystallographer. The oscillations carried out during data"
"Survey marker Survey markers, also called survey marks, survey monuments, survey benchmarks or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying. Informally, such marks are referred to as benchmarks, although strictly speaking the term ""benchmark"" is reserved for marks that indicate elevation. Horizontal position markers used for triangulation are also known as triangulation stations. All sorts of different objects, ranging from the familiar brass disks to liquor bottles, clay pots, and rock cairns, have been used over the years as survey markers. Some truly monumental markers"
"Magnetic survey (archaeology) Magnetic survey is one of a number of methods used in archaeological geophysics. Magnetic surveys record spatial variation in the Earth's magnetic field. In archaeology, magnetic surveys are used to detect and map archaeological artefacts and features. Magnetic surveys are used in both terrestrial and marine archaeology. Magnetometers used in geophysical survey may use a single sensor to measure the total magnetic field strength, or may use two (sometimes more) spatially separated sensors to measure the gradient of the magnetic field (the difference between the sensors). In most archaeological applications the latter (gradiometer) configuration is preferred because"
"and is better suited for dynamic and advanced studies. Contact angle goniometers (q.v.)can also determine the surface tension for any liquid in gas or the interfacial tension between any two liquids. If the difference in densities between the two fluids is known, the surface tension or interfacial tension can be calculated by using the pendant drop method. An advanced instrument often called a goniometer / tensiometer will include software tools to measure surface tension and interfacial tension using the pendant drop, inverted pendant drop, and sessile drop methods - in addition to contact angle. A centrifugal adhesion balance is used"
"Gonioscopy Gonioscopy describes the use of a goniolens (also known as a gonioscope) in conjunction with a slit lamp or operating microscope to gain a view of the iridocorneal angle, or the anatomical angle formed between the eye's cornea and iris. The importance of this process is in diagnosing and monitoring various eye conditions associated with glaucoma. The goniolens allows the clinician - usually an ophthalmologist or optometrist - to view the irideocorneal angle through a mirror or prism, without which the angle is masked by total internal reflection from the ocular tissue. The mechanism for this process varies with"
"collection (mentioned below) involve the ω axis only. An older type of goniometer is the four-circle goniometer, and its relatives such as the six-circle goniometer. Small scale can be done on a local X-ray tube source, typically coupled with an image plate detector. These have the advantage of being (relatively) inexpensive and easy to maintain, and allow for quick screening and collection of samples. However, the wavelength light produced is limited by anode material, typically copper. Further, intensity is limited by the power applied and cooling capacity available to avoid melting the anode. In such systems, electrons are boiled off"
"Gyrotheodolite In surveying, a gyrotheodolite (also: surveying gyro) is an instrument composed of a gyroscope mounted to a theodolite. It is used to determine the orientation of true north. It is the main instrument for orientation in mine surveying and in tunnel engineering, where astronomical star sights are not visible and GPS does not work. In 1852, the French physicist Léon Foucault discovered that a gyro with two degrees of freedom points north. This principle was adapted by Max Schuler in 1921 to build the first surveying gyro. In 1949, the gyro-theodolite – at that time called a ""meridian pointer"""
"is usually carried out using total stations and recorded using data collectors. Location positions are also determined using GNSS. Traditional methods and instruments are still in use in many areas of the world and by users who are not primarily surveyors. A ""tachymeter"" or ""tacheometer"" is a type of theodolite used for rapid measurements and determines, electronically or electro-optically, the distance to target. The principles of action are similar to those of rangefinders. Other forms of tacheometry in surveying include the use of stadia rods with theodolites or plane-table alidades. These use stadia marks on the instrument's reticle to measure"
"therapist will assess the joint before performing an intervention and will continue to use the tool to make sure that progress is made. These range of motion measurements can be taken at any joint and they typically involve some knowledge about the anatomy of the body, particularly bony landmarks. For example, when measuring the knee joint, the axis (point of rotation) would be placed on the lateral epicondyle of the femur, while the stationary arm would be lined up with the greater trochanter of the femur. Finally, the moveable arm of the goniometer would be lined up with the lateral"
"because it provides very dense information in an analog and surprisingly intuitive form. From the display, one can get a good feel for the audio levels for each channel, the amount of stereo and its compatibility as a mono signal, even to some degree what frequencies are contained in the signal. Experts may even be able to determine the probable arrangement of microphones when the signal was recorded. Goniometer (audio) A goniometer is often included in analog audio equipment to display a Lissajous figure which shows the amount of stereo (that is, phase differences) in a dual-channel signal. It allows"
"on the panel of the Ryan NYP ""The Spirit of St. Louis""—in 1927 Charles Lindbergh chose the lightweight Rieker Inc P-1057 Degree Inclinometer to give him climb and descent angle information. Hand-held clinometers are used for a variety of surveying and measurement tasks. In land surveying and mapping, a clinometer can provide a rapid measurement of the slope of a geographic feature, or used for cave survey. In prospecting for minerals, clinometers are used to measure the strike and dip of geologic formations. In forestry, tree height measurement can be done with a clinometer using standardized methods. Major artillery guns"
"best picture. Archaeologists have to still dig up the area in order to uncover the truth. There are also two most common types of geophysical survey, which is, magnetometer and ground penetrating radar. Magnetometry is the technique of measuring and mapping patterns of magnetism in the soil. It uses an instrument called a magnetometer which is required to measure and map traces of soil magnetism. The ground penetrating radar is a method that uses radar pulses to image the subsurface. It uses electro magnetic radiation in the microwave band of the radio spectrum, and detects the reflected signals from subsurface"
"can also assist when coal seams are deep, by using multiple sills or looking beneath surface basalt flows. Modern surveys generally use magnetometers with GPS technology to automatically record the magnetic field and their location. The data set is then corrected with data from a second magnetometer (the base station) that is left stationary and records the change in the Earth's magnetic field during the survey. Magnetometers are used in directional drilling for oil or gas to detect the azimuth of the drilling tools near the drill. They are most often paired with accelerometers in drilling tools so that both"
"a 1 kHz mono tone) so that the output produces a vertical plot line. If one channel were phase-inverted, it would result in the plot line being a horizontal instead of vertical, a sure sign of problems. As for mono signals, a half-inverted signal would be reduced to (near) silence. The persistence of a CRT display is a desired effect on goniometers because the signal display is very dynamic, and the overall shape or envelope of the signal is the object of interest. In fact, good digital and software goniometers provide artificial and even user-adjustable persistence. The goniometer proves useful"
"organized by the World Meteorological Organization (WMO), which also use these instruments to report weather conditions at their respective locations. A sounding rocket or rocketsonde, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its suborbital flight. A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface and is a sensor that is designed to measure the solar radiation flux density (in watts per metre square) from a field of view of 180 degrees. A ceilometer is a device that uses a laser or"
"gather the statistical information upon which the Bill was founded, as well as determining the boundaries and districts of boroughs. It was said that the fate of numerous boroughs fell victim to the heliostat and the Drummond light, the instrument that Drummond invented whilst surveying in Ireland. An Abney level is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale. The Abney level is an easy to use, relatively inexpensive, and when used correctly an accurate surveying tool. The Abney level was"
"Planimetrics Planimetrics is the study of plane measurements, including angles, distances, and areas. To measure planimetrics a planimeter is used. This rather advanced analog technology is being taken over by simple image measurement software tools like, ImageJ, Adobe Acrobat, Google Earth Pro, Gimp, Photoshop and KLONK Image Measurement which can help do this kind of work from digitalized images. Planimetric elements in geography are those features that are independent of elevation, such as roads, building footprints, and rivers and lakes. They are represented on two-dimensional maps as they are seen from the air, or in aerial photography. These features are"
"Some EM conductivity instruments are also capable of measuring magnetic susceptibility, a property that is becoming increasingly important in archaeological studies. Magnetometers used in geophysical survey may use a single sensor to measure the total magnetic field strength, or may use two (sometimes more) spatially separated sensors to measure the gradient of the magnetic field (the difference between the sensors). In most archaeological applications the latter (gradiometer) configuration is preferred because it provides better resolution of small, near-surface phenomena. Magnetometers may also use a variety of different sensor types. Proton precession magnetometers have largely been superseded by faster and more"
"some information on the material in each layer. Magnetic surveying can be done on a planetary scale (for example, the survey of Mars by the Mars Global Surveyor) or on a scale of meters. In the near-surface, it is used to map geological boundaries and faults, find certain ores, buried igneous dykes, locating buried pipes and old mine workings, and detecting some kinds of land mines. It is also used to look for human artifacts. Magnetometers are used to search for anomalies produced by targets with a lot of magnetically hard material such as ferrites. High precision gravity measurements can"
"Oedometer test An oedometer test is a kind of geotechnical investigation performed in geotechnical engineering that measures a soil's consolidation properties. Oedometer tests are performed by applying different loads to a soil sample and measuring the deformation response. The results from these tests are used to predict how a soil in the field will deform in response to a change in effective stress. Oedometer tests are designed to simulate the one-dimensional deformation and drainage conditions that soils experience in the field. To simulate these conditions, rigid confining rings are used to prevent lateral displacement of the soil sample. Porous stones"