| 释义 |
base line
base·line or base line B5098500 (bās′līn′)n.1. a. A line serving as a basis, as for measurement, calculation, or location.b. Something, such as a set of data, used as a basis for comparison or as a control in a study: took x-rays as a baseline for observing later arthritis. c. A starting point: Interviews with students provided the baseline of our project.2. Baseball The base path.3. Sports a. The boundary line at either end of a court, as in basketball or tennis.b. The area near this boundary line: made a basket from the baseline.c. A style of play in tennis in which the player remains near the baseline and rarely approaches the net.base line1. (surveying) A surveyed line established with more than usual care, to which surveys are referred for coordination and correlation.
2. (photogrammetry) The line between the principal points of two consecutive vertical air photographs. It is usually measured on one photograph after the principal point of the other has been transferred.
3. (radio navigation systems) The shorter arc of the great circle joining two radio transmitting stations of a navigation system.
4. (triangulation) The side of one of a series of coordinated triangles the length of which is measured with prescribed accuracy and precision and from which lengths of the other triangle sides are obtained by computation.base line
base line: see geodesygeodesy
or geodetic surveying,
theory and practice of determining the position of points on the earth's surface and the dimensions of areas so large that the curvature of the earth must be taken into account.
..... Click the link for more information. .base line[′bās ‚līn] Abbreviated BL. (electronics) The line traced on amplitude-modulated indicators which corresponds to the power level of the weakest echo detected by the radar; it is retraced with every pulse transmitted by the radar but appears as a nearly continuous display on the scope. (engineering) A surveyed line, established with more than usual care, to which surveys are referred for coordination and correlation. A cardinal line extending east and west along the astronomic parallel passing through the initial point, along which standard township, section, and quarter-section corners are established. (graphic arts) The bottom alignment of upper-case letters in a font. (navigation) The geodesic line joining the two stations between which electrical phase or time is compared in determining navigational coordinates. (science and technology) A line drawn in the graphical representation of a varying physical quantity, such as a voltage or current, to indicate a reference value, such as the voltage value of a bias. base lineA surveyed line which has been established with more than usual care, and to which surveys are referred for coordination and correlation.base line
or·bi·to·mea·tal plane1. a line approximating the base of the cranium, passing from the infraorbital ridge to the midline of the occiput, intersecting the superior margin of the external auditory meatus; the cranium is in the anatomic position when the base line lies in the horizontal plane and right and left sides are level. 2. a standard craniometric reference plane passing through the right and left porion and the left orbitale; drawn on the profile radiograph or photograph from the superior margin of the acoustic meatus to the orbitale. Synonym(s): auriculoinfraorbital plane, eye-ear plane, Frankfort horizontal plane, Frankfort plane, infraorbitomeatal planebase lineAn imaginary cephalometric line from the infraorbital ridge through the middle of the external auditory meatus to midline of occiput.See also: lineBase Line
Base LineSurvey line used in the government survey to establish township lines. Horizontal elevation line used as a centerline in a highway survey. FinancialSeebaseline |