- 行业: Earth science
- Number of terms: 93452
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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, ...
The requirement that the sum of the squares of the differences between the measured values in a set and the corresponding calculated values be a minimum the values being a function of a set of variables which can be given values more or less arbitrarily.
Industry:Earth science
The misclosure in azimuth or angle is first distributed in equal portions to all the measured angles. The adjusted angles are then held fixed and all remaining corrections distributed among the measurements of distance through the method of weighted least squares.
Industry:Earth science
(1) Pass or transmit the title to property from one to another. (2) Transfer property or the title to property by deed or instrument under seal. The term applies properly to the disposition of real property, not of personal property. To convey real estate, by an appropriate instrument, is to transfer the legal title to it from the present owner to another.
Industry:Earth science
A reference surface (for plane coordinates), above or below the reference surface on which the plane coordinate system was originally placed by mathematical procedures. The new surface is always parallel to the original surface. Its location above or below the original surface is governed by the degree to which the inherent difference can be reduced between (a) distance measured on the ground and (b) distance computed using plane coordinates of points and features delineated on maps or surveyed distance computed and/or measured on the adjusted datum.
Industry:Earth science
(1) A large mass of land rising abruptly from the bottom of the oceanic deep and including marginal regions that are shallowly submerged. (2) One of the land masses identified as continents and named Africa, Antarctica, Asia, Australia, Europe, North America and South America. Greenland is sometimes included. There is disagreement over the validity of classifying Europe and Asia as separate continents if a geological basis is wanted for the classification. Modern evidence indicates, however, that at one time the two continents were up to 3000 km apart.
Industry:Earth science
The addition of control throughout a region in which control has already been established. Unless otherwise specified, geodetic control may be assumed to be meant.
Industry:Earth science
(1) A right-handed, rectangular Cartesian coordinate system which has the z-axis perpen-dicular to the plane of the Earth's orbit and the x axis parallel to the line of intersection of the plane of the Earth's orbit with the plane of the celestial equator. Only the system's orientation is defined. The origin may be anywhere in the Solar system but is usually placed in the Earth or in the Sun. (2) A coordinate system whole geometric elements are a straight line (called the polar axis or z-axis), a straight line (called the x axis) intersecting the z-axis at right angles, and the point (called the origin) at which the z axis intersects the x,y-plane. The coordinates of a point are the angle (called the longitude) from the plane of the z and x-axes to the plane through the z axis and the point in question; the angle (called the latitude) which is the complement of the angle from the z-axis to a line joining the origin to the point in question; and the distance from the origin to the point in question.
Industry:Earth science
A matrix whose element in row i and column j is the average value of (x<sub>i</sub> - μ<sub>I</sub>)(x<sub>j</sub> - μj), where x<sub>i</sub> and x<sub>j</sub> are random variables with average values μ<sub>i</sub> and μ<sub>j</sub>, respectively. The elements along the main diagonal are called the variances of the corresponding variables; the elements off the main diagonal are called the covariances.
Industry:Earth science
A combination of two sets of closely spaced, parallel lines, the one set crossing the other at a predetermined angle. It is used on charts and maps to designate or distinguish particular kinds of terrain, etc.
Industry:Earth science
A coordinate system which has its origin at a point with known geodetic coordinates and its axes oriented with respect to astronomic north and the astronomic meridian of Greenwich. This is equivalent to defining the system by giving the geodetic and astronomic coordinates of a point in the system.
Industry:Earth science
