- Industry: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- 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, ...
An optical filter which transmits principally light of a certain polarization and substantially attenuates light polarized in other directions. The more common varieties are made of plastic in which polarization selective crystals are suspended. The term polarizing filter is misleading. The filter does not polarize the light transmitted; it merely does not transmit well light polarized in directions other than those permitted by the filter's structure. This is why a scene viewed through a polarizing filter appears darker than when seen without; much of the light does not get through.
Industry:Earth science
That side (the top or smooth side) which is in contact with the felt belt for extracting moisture during manufacture. This is the correct side of the paper for printing on.
Industry:Earth science
A unit of length equal exactly to 1/6 toise. The French foot contained exactly 12 lignes and was approximately 0.31 meters long.
Industry:Earth science
The projected angle of the field stop, as seen through the eyepiece.
Industry:Earth science
A set of overlapping strips of photographs, considered as a unit for photogrammetric adjustment. The smallest flight-block consists of at least three, overlapping strips.
Industry:Earth science
One of the two rotational ellipsoids calculated by I. Fischer. (1) The ellipsoid used for the Mercury datum has the dimensions<br>
Industry:Earth science
Motion of a fluid when the horizontal component of the pressure does not balance the horizontal component of Coriolis force per unit of area.
Industry:Earth science
An optical filter whose density decreases radially from the center to compensate for the radially decreasing illumination given by certain kinds of lens systems, particularly wide angle lens systems. The filter may be a separate piece of glass with a partly transparent coating of varying thickness, or it may be the coating itself deposited directly on one of the elements of the lens system. It does not prevent vignetting; it merely obscures the effect of vignetting by reducing the amount of light reaching non vignetted portions of the image.
Industry:Earth science
A mathematical function or algorithm which selects some numbers from a finite or infinite set of numbers and rejects the rest according to preset criteria, and creates other numbers to represent those rejected. The function or algorithm does not, in making its selection, make any use of the values it creates.
Industry:Earth science
(1) The effective transmittance of an optical filter. (2) A number indicating the increase in amount of time needed for exposure of a photographic emulsion when using an optical filter, as compared to the amount of time needed when no filter is used.
Industry:Earth science
