- Branża: Earth science
- Number of terms: 93452
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- Company Profile:
Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
A combination of two or more cameras mounted with a fixed angle between their respective optical axes.
Industry:Earth science
The smallest angle at which a wave passing from a substance of higher refractive index to one of lower refractive index can be incident on the surface between the substances and be totally reflected at that surface. At the critical angle, some of the waves may propagate along the surface. At angles less than critical, some or all of electromagnetic waves propagate into the surface. The angle is expressed by the formula sin(critical angle) = N'/N, in which N is the higher refractive index and N' is the lower.
Industry:Earth science
A concurrence, between owners of adjoining lands, on the location of their common boundaries, defined in the exercise of good judgment by the parties to the stipulation as needed for interpretation by disinterested persons, including one qualified in land surveying, and as ordinarily required in a deed, subject to judicial opinion in the event of ambiguity or controversy.
Industry:Earth science
A number v introduced by E. Abbe for characterizing an optical medium by its dispersion, and defined by the formula v = (n<sub>d</sub>-1)/(n<sub>F</sub>-n<sub>c</sub>), in which n<sub>d</sub>, n<sub>F</sub>, n<sub>c</sub> are the refractive indices of the medium at the wave-lengths of, respectively, the helium d-line, the Fraunhofer F-line and the Fraunhofer C-line. The number is used, in particular, in computations for designing achromatic systems of lenses. For example, an optical system of two lenses has the same focal length at each of the wavelengths of the F and C-lines when the sum of the products of the Abbe numbers and the focal lengths of the individual lenses is equal to zero.
Industry:Earth science
An old measure of length, equal to the average length of a grain of barley; the third part of an inch.
Industry:Earth science
A figure within which the true location of a point whose location has been determined by measurement is believed to lie, with stated degree of probability.
Industry:Earth science
In analytical photogrammetry, the separation of images into annular zones defined by specific bands contained within, usually, 5°of arc. Regions read then lie only in certain outer bands depending on, the calibration of the lens cone.
Industry:Earth science
A level surface from which vertical distances are measured or calculated.
Industry:Earth science
A device for measuring acceleration. A common type is simply a pendulum suspended from a pivot fixed in the accelerating body. As the body accelerates, the pendulum is deflected through an angle which depends on the amount of acceleration. Another common type consists of a mass held in equilibrium by springs that are fixed to the accelerating body. The amount of acceleration is determined from the amount of distortion in the springs. Masses resting on strain gages have also been used to measure acceleration. A particularly sensitive type, used in artificial satellites, encloses a spherical test mass within a slightly larger sphere. The test mass is kept centered by suitable means, and changes (caused by acceleration) in location of the test mass with respect to its inclosure are measured by changes in capacitance between the two surfaces.
Industry:Earth science
