- 行业: 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, ...
A tidal constituent that has two maxima and two minima each constituent day.
Industry:Earth science
(1) A coordinate system having (a) its origin at the center of mass of the Moon, (b) a reference plane through the origin and parallel to the plane of the ecliptic, and (c) a reference plane through the origin, perpendicular to the first reference plane, and parallel to the line of equinoxes. Selenocentric longitude is measured counterclockwise (as seen from the north pole of the ecliptic) from the second reference plane to a plane through the origin, perpendicular to the first reference plane, and through the point of interest. Selenocentric latitude is measured positively northward from the first reference plane to a line joining the origin to the point of interest. (2) A coordinate system having its origin at a central point (either the center or mass or the geometric center) of the Moon. This usage is deprecated.
Industry:Earth science
(1) A corner, on a standard parallel or base line, which serves as a starting point for surveys to the north. (2) A corner on a standard parallel or base line.
Industry:Earth science
In the relative orientation of two photographs, the cumulative warpage of the models affecting the horizontal datum because of errors in the z-motion, bridging and swing.
Industry:Earth science
Any point of known or assumed coordinates used as a reference which measurements or calculations may be taken.
Industry:Earth science
The curvature, at a point P on a surface, of the curve which is the intersection of a plane through the normal to the surface and a tangent to the surface. For any point, the value of the normal curvature changes as the direction of the tangent changes. For any regular surface, there is one direction in which the normal curvature is a maximum and another direction in which the normal curvature is a minimum. These two directions are called the principal directions and the corresponding curvatures are called the principal curvatures.
Industry:Earth science
A hypothetical line separating two neighboring time zones in which the civil dates differ by one day. The term is often used to designate the international date line. It is written, on charts of the U. S. Hydrographic office, as Dateline.
Industry:Earth science
(1) That offset from the tangent to the curve resulting from curvature of the Earth. The offset amounts to about 8 cm at 1 km distance. (2) That offset which is given in surveying tables as correction for curvature of the Earth. The values given in such tables usually combine the effects of both curvature of the Earth and atmospheric refraction. Under normal conditions, the atmospheric refraction compensates partially for the curvature of the Earth, so the correction is about 6 cm for a point 1 km away.
Industry:Earth science
In mechanics, the interaction of two independent events to produce another event. If a way can be found to prevent the original events from acting on each other, the events are said to be decoupled. e.g., when a gravimeter is used on board a ship, cross coupling takes place between vertical and horizontal motions of the ship and the vertical reaction of the gravimeter. This causes the gravimeter to give erroneous readings of gravity.
Industry:Earth science
(1) A survey network in which the stations are control stations. (2) Geodetic control together with the measured and/or adjusted values of distances, angles, directions and/or heights used in determining the coordinates of the control.
Industry:Earth science
