- 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, ...
A system of units in which the fundamental quantities are: the constant of universal gravitation, the charge on the electron, the magnetic constant and the electric constant. Length, mass and time are derived quantities.
Industry:Earth science
To assemble and fit together separate, individual photographs so that the assemblage is a continuous, consistent picture of the entire region or object depicted by the individual photographs.
Industry:Earth science
(1) The vertical plane in which a freely suspended, symmetrically magnetized needle, influenced by no transient, artificial, magnetic disturbance, will come to rest. (2) The curve, on the Earth's surface at all points of which the vertical plane described in the preceding definition is tangent to the curve. (3) The direction, at any point, of the horizontal component of the Earth's magnetic field.
Industry:Earth science
Navigation in which locations are determined as differences of distance from three or more fixed points on land. Equivalently, navigation using a hyperbolic navigation system. A hyperbolic navigation system determines a difference in distance (measured in wavelengths) of a mobile unit from three or more stationary, fixed units. The locus of points all of which have the same difference of distance from two of these units is a hyperbola. Taking the fixed units in two pairs (one unit common to both, if there are only three units), two intersecting hyperbolas are determined. The mobile unit is located at one of the two points where the two hyperbolas intersect.
Industry:Earth science
A map on which isolines represent lines on the ground or other surface along which the gravitational acceleration is constant.
Industry:Earth science
A map of one-half of the Earth's surface (or of one half of a sphere) and bounded by the Equator or by another great circle. The Earth is usually considered to be divided either at the Equator, into the Northern and Southern Hemispheres, or along some meridian (continued around the globe) between Europe and America, into Eastern and Western Hemispheres. Cartographers usually divide the Earth along the meridians of longitude passing through 20<sup>o</sup> West and 160<sup>o</sup> East. The Americas are considered to be in the Western Hemisphere.
Industry:Earth science
The bearing, of a straight line plotted on a chart on a Mercator map projection, as taken from the chart. It is the angle from a line representing the meridian to the straight line.
Industry:Earth science
Commonly, a map at a scale equal to or smaller than 1:500 000. This criterion is by no means universally used.
Industry:Earth science
A map projection such that on lines representing meridians, equal meridional distances are intercepted everywhere between the same lines representing parallels of latitude. This is not strictly a polyconic map projection.
Industry:Earth science
