Use the “Quick Search” box to locate your required term and/or definition. The following “Search conditions” can be used to refine your search: “Contains”, “Begins with”, “Ends with”, “Equals”, “Does not contain” or “Does not equal.”
Eng ID Term Definition
2761
level: tilting
See LEVELLING INSTRUMENT: TILTING LEVEL.
2762
level: universal
See LEVEL: SPIRIT.
2763
level: Y
See LEVELLING INSTRUMENT: Y LEVEL.
2764
level axis
See AXIS OF SPIRIT LEVEL.
2765
level ice
SEA ICE with a flat surface which has never been hummocked.
2766
levelling (or leveling)
The operation of determining differences of ELEVATION between points on the surface of the EARTH; the determina­tion of the ELEVATION of poi... more
The operation of determining differences of ELEVATION between points on the surface of the EARTH; the determina­tion of the ELEVATION of points relative to some arbitrary or natural LEVEL SURFACE called a DATUM. Also called differential levell­ing.
2767
levelling: barometric
A method of determining diffe­rences of ELEVATION from differences of ATMOSPHERIC PRESSURE observed with a BAROMETER.
2768
levelling: direct
The determination of differences of ELEVATION by a continuous series of short horizontal lines. Vertical distances from these lines to adjac... more
The determination of differences of ELEVATION by a continuous series of short horizontal lines. Vertical distances from these lines to adjacent ground marks are determined by direct OBSERVATIONS on graduated rods with a LEVELLING INSTRUMENT equipped with a SPIRIT LEVEL.
2769
levelling: geodetic
SPIRIT LEVELLING of a high order of ACCURACY, usually extended over large areas, to fur­nish accurate VERTICAL CONTROL as a basis for the CO... more
SPIRIT LEVELLING of a high order of ACCURACY, usually extended over large areas, to fur­nish accurate VERTICAL CONTROL as a basis for the CONTROL in the vertical dimension for all surveying and mapping operations.
2770
levelling: indirect
The determination of differences of ELEVATION from (a) vertical angles and horizon­tal distances, as in TRIGONO­METRIC LEVELLING; (b) compar... more
The determination of differences of ELEVATION from (a) vertical angles and horizon­tal distances, as in TRIGONO­METRIC LEVELLING; (b) compara­tive ELEVATIONS derived from values of ATMOSPHERIC PRESSURE deter­mined with a BAROMETER, as in BAROME­TRIC LEVELLING; and (c) ELEVATIONS derived from values of the boiling point of water determined with a HYPSOME­TER, as in THERMOMETRIC LEVELLING.
2771
levelling: reciprocal
TRIGONOMETRIC LEVELLING wherein vertical angles have been observed at both ends of the line to eliminate ERRORS.
2772
levelling: spirit
The determination of ELEVATIONS of points with respect to each other or with respect to a common DATUM, by use of a LEVELLING ROD and an ins... more
The determination of ELEVATIONS of points with respect to each other or with respect to a common DATUM, by use of a LEVELLING ROD and an instru­ment using a SPIRIT LEVEL to establish a horizontal LINE OF SIGHT.
2773
levelling: thermometric
The determination of ELEVATI­ONS above SEA LEVEL from observed values of the boiling point of water. See HYPSOMETER.
2774
levelling: trigonometric
The determination of diffe­rences of ELEVATIONS by means of observed vertical angles, combined with lengths of lines.
2775
levelling: water
A method of obtaining relative ELEVA­TIONS by observing HEIGHTS with respect to the surface of a body of still water, such as a LAKE. The re... more
A method of obtaining relative ELEVA­TIONS by observing HEIGHTS with respect to the surface of a body of still water, such as a LAKE. The relative ELEVATIONS of objects along its SHORES are obtained by taking the differences of their HEIGHTS with respect to the surface of the water.
2776
levelling instrument
An instrument designed for the accurate measurement of height differences by the process of LEVELLING. Its essential parts are a TELE­SCOPE ... more
An instrument designed for the accurate measurement of height differences by the process of LEVELLING. Its essential parts are a TELE­SCOPE and a SPIRIT LEVEL. Also called a LEVEL.
2777
levelling instrument: dumpy level
A LEVELLING INSTRU­MENT which has its TELESCOPE permanently attached to the levelling base, either rigidly or by a hinge that can be manipul... more
A LEVELLING INSTRU­MENT which has its TELESCOPE permanently attached to the levelling base, either rigidly or by a hinge that can be manipulated by a MICROMETER SCREW.
2778
levelling instrument: self-aligning level
A LEVEL in which a sensitive prism element inside the TELESCOPE acts on the principle of the PENDULUM and ensures that the LINE OF SIGHT is ... more
A LEVEL in which a sensitive prism element inside the TELESCOPE acts on the principle of the PENDULUM and ensures that the LINE OF SIGHT is horizontal, even if the axis of the TELESCOPE is several MINUTES out of the HORIZON­TAL.
2779
levelling instrument: tilting level
A LEVELLING IN­STRU­MENT in which the final LEVELLING of the instrument is obtained by small con­trolled amounts of rota­tion of the TELESCO... more
A LEVELLING IN­STRU­MENT in which the final LEVELLING of the instrument is obtained by small con­trolled amounts of rota­tion of the TELESCOPE about a HORIZONTAL AXIS.
2780
levelling instrument: Y level
A LEVELLING INSTRUMENT having the TELESCOPE, with attached SPIRIT LEVEL, supported in Y's. The TELESCOPE can be rotated about its lon­gitudi... more
A LEVELLING INSTRUMENT having the TELESCOPE, with attached SPIRIT LEVEL, supported in Y's. The TELESCOPE can be rotated about its lon­gitudinal axis in the Y's and it can be lifted and revers­ed, end for end.