- Branche: Earth science
- Number of terms: 93452
- Number of blossaries: 0
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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 thin, flexible, transparent sheet (film) of stable, plastic material (the base or film base) coated with a light sensitive material (the emulsion) and used for taking photographs. Commonly referred to as film if it is perfectly clear from the context that photographic film is meant. Unfortunately, film is often used as if it were a complete synonym, with resulting confusion in some places. Photo-graphic film and film are also often applied to the final product after exposure, development and fixing. However, that product is more commonly referred to as a negative or a positive, according to the nature of the final image. Photographic film is distinguished from photographic plate in that the latter has the emulsion coated onto a rigid material, usually glass.
Industry:Earth science
The force, in the direction of the normal, required to constrain a body to move in a closed, curved path. Centripetal force acts in the direction toward the center of curvature of the path followed by the body. It is equal and opposite to centrifugal force. It, and the centrifugal force, are sometimes called fictitious forces or quasi-forces because the observed effects can be explained without introducing such forces.
Industry:Earth science
The intensity of the horizontal component of the magnetic field in the plane of the magnetic meridian.
Industry:Earth science
A slow, nearly monotonic variation (drift) in frequency. For example, a slow rise or fall of the temperature of a crystal oscillator, or aging of the components in the circuit, will cause the oscillator's frequency to change slowly in one direction. Frequency drift cannot, in general, be completely controlled or its amount predicted.
Industry:Earth science
(1) First one and then the other of a pair of corresponding images (photographic or other) are projected alternately and in rapid succession onto a flat surface such as a table or screen, or into the optical system of a photogrammetric apparatus for simultaneous viewing with both eyes. The viewer sees a flickering in those parts of the composite image where the corresponding images differ in detail. (2) First one picture of a stereoscopic pair is viewed by one eye and then the other picture is viewed by the other eye, the viewings taking place alternately and in rapid succession, as by blinking first of one eye and then the other. The viewer gets the impression of a single, fused picture. A flickering will be noticed in those regions of the composite where the two pictures differ appreciably in detail. The effect is usually obtained without making the viewer blink, by placing the two pictures side by side but separated by a thin partition placed so that each eye of the viewer can see only one picture. The pictures are then illuminated rapidly and alternately.
Industry:Earth science
That temperature above which a liquid remains liquid and at which a liquid solidifies. The term is applied, in particular, to the behavior of pure water, which has its freezing point at 0<sup>o</sup> C (32<sup>o</sup> F.). Note that the melting point and freezing point may not be the same.
Industry:Earth science
A circuit which substantially attenuates the amplitudes of those components of a varying current or voltage which are present within a specified range of frequencies. A low pass filter removes all frequencies lower than the one specified, a high pass filter removes all frequencies higher than the one specified, and a band pass filter removes all filters above or below a specified range. A passive filter contains no source of power and is a combination of resistances, capacitances and/or inductances. An active filter contains an amplifier or similar element such as a transistor which differentially amplifies the wanted frequencies or attenuates the unwanted ones.
Industry:Earth science
Determining the contours for a topographic map by making a planetable survey on a prepared sheet or by stadia surveying. This operation is generally used for mapping terrain unsuitable for mapping by photogrammetric methods. It is also used in regions of limited extent when the engineering plan requires contour lines at 1 foot (0.3 m) intervals.
Industry:Earth science
(1) An estate of inheritance. (2) An inheritance for life or an estate during the life of a third person.
Industry:Earth science
