- Branche: 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 astrolabe whose distinctive feature is a mirror fixed to the top of a pendulum suspended in such a way as to form an artificial horizon for the line of sight. The telescope is placed so that observations are made at a constant angular elevation. In one form, the instrument consists of a V-shaped casting carrying the objective and eyepiece lenses at the tops of the V (placed vertically). The mirror, which rests on top of the pendulum and forms the artificial horizon, is located at the bottom of the V. The pendulum is suspended so that it is free to swing in either of two planes at right angles to each other (e.g., in north south and east west planes). The pendulum's motion is highly damped so that the mirror comes to rest quickly and remains steady under normal conditions.
Industry:Earth science
An agreement that permits one to buy or sell property or an interest therein within a stipulated time, in accordance with the terms of the agreement.
Industry:Earth science
The name of a system of witnessing corner stakes of a public-land survey in a prairie.
Industry:Earth science
A tower constructed to permit sighting from an observing instrument to a distant point. The tower may be of wood, steel, or other strong material. It may be of triangular or rectangular cross-section. If very precise measurements are to be made from it, it usually consists of two separate structures: an inner structure supporting only the instrument and an outer structure supporting the observer and auxiliary equipment.
Industry:Earth science
An ordinance providing for and regulating development within a planned community.
Industry:Earth science
A modified Carpentier inversor coupled to the linkage of a Peaucellier inversor.
Industry:Earth science
At any given point (x,y) on a surface, the curvature κ of every curve, in the plane and through that point, whose osculating plane makes an angle α with the plane of the normal section through the same tangent is κ <sub>n</sub> / cos α , in which κ <sub>n</sub> is the curvature of the normal section through the tangent at the point.
Industry:Earth science
The act or process of modifying electromagnetic radiation in such a way that the electro-magnetic field has the same value (intensity and phase) at all points in a plane perpendicular to the direction of propa-gation of the radiation. A more picturesque description would be that all the waves in the beam go up and down in planes parallel to each other and to the direction of propagation.
Industry:Earth science
A period of 19 years adopted by the National Ocean Survey as the period over which observations of tides are to be taken and reduced to average values for tidal datums. The epoch is designated by giving the year the period began and the year it ended, e.g., National Tidal Datum Epoch of 1941 through 1959.
Industry:Earth science
(1) Any thing or any event able to be seen or otherwise detected or sensed, and noted. (2) Any measurable thing or event. (3) A quantity present as an unknown in an equation and whose value is to be found. This usage is misleading and appears to be used as jargon by some statisticians.
Industry:Earth science
