| Term | Meaning |
|---|
| a posteriori | value estimated from measurements (observations) |
| a priori | value known prior to (before) the measurements, based on experiences |
| barycentre | centre of mass of points or curves or areas, possibly including weights |
| blind target point | target point without measurements, used in the universal computer to generate polar values r,t,v,s,e for this target |
| Bonferroni equation | For multiple hypothesis tests the probability of type I decision error is portioned equally to all single tests |
| central meridian | For grid systems (UTM, Gauss-Krüger etc.) the meridian in the middle of the meridian strip |
| collimation error | Deviation of the optical axis of the telescope from the plane perpendicular to the horizontal axis of the instrument |
| collinear | located on the same straight line |
| common normal | shortest connection between two skew straightlines, is perpenticular on either line |
| coplanar | located on the same plane |
| concave | dished or hollowed inward |
| confidence level | probability that the confidence region covers the true value or point |
| control points | also ´´identical´´ or ´´homologous´´ points: transformation points with identical names and given coordinates in both systems |
| convex hull | smallest convex set, that contains all given points |
| curve equation | equation, that is fulfilled for points in the curve, but not for others |
| default value | in a data list pads all missing values of this data type or column |
| equirectangular projection | also ´´equidistant cylindrical projection´´: The meridians and parallels form a lattice of equisized rectangles. |
| error propagation | transfer of errors in the input quantities to the output quantity, amplification or attenuation may occur |
| Eulerian angle | one of three rotation angles, which can be used to transform one spatial system into another by three rotations about defined axes |
| Eulerian axis | rotation axis through the origin, about which one spatial system can be transformed into another by a single rotation, represented by three vector components |
| excess kurtosis | indicates, how thin or thick the tails of the measurement distribution are, in comparison to the Gaussian normal distribution. Excess kurtosis < 0: thin-tailed (blunt peaked), = 0: normal shape (Gaussian bell), > 0: thick-tailed (sharp peaked) |
| false easting | Easting at the central meridian, usually 500000. Change, when using abbreviated eastings! |
| false northing | Northing at the equator, on the northern hemisphere usually 0. Change, when using abbreviated northings! |
| geodesic | shortest curve inside a surface (here: ellipsoid of revolution), which connects two given points |
| global test | also ´´overall model test´´: a χ² test, checks if the prior and posterior standard deviations are in sufficient agreement |
| grid system | geodetic coordinate system defined on a meridian strip, which can be conformally (true angle) mapped to the plane. Best known are UTM and Gauss-Krüger. The coordinates are called northing, easting, height |
| group refractivity | refractivity referring to the group velocity (signal velocity) of the wave packet |
| information criterion | criterion for the selection of a model in statistics. If we have stochastic observations and a set of model candidates at our disposal, then we compute for all candidates the corresponding value of the information criterion. A small value indicates that a model is adequate |
| interquartile range | width of the interval excluding the 25% smallest and 25% largest values = difference of the third and first quartile |
| isometric latitude | latitude whos parallels, together with the meridians, form a grid of squares on the ellipsoid, which become smaller and smaller towards the poles |
| lefthanded | X=thumb, Y=forefinger, Z=middle finger of the LEFT hand, line of sight onto palm |
| matrix condition | indicates the degree of error amplification during the adjustment solution |
| median | in a sorted list of congeneric values the one at the midpoint of the list |
| normal atmosphere | atmospheric conditions, for which the distance measurement value to be corrected would be valid |
| normal gravity | value of the gravity acceleration in the normal gravity field, a simple model of the true gravity field of the Earth |
| parallel | also ´´circle of latitude´´: circle on the reference ellipsoid, connecting all locations having a given latitude |
| phase refractivity | refractivity referring to the phase velocity (velocity of a wave front) of the wave packet |
| polygonal diameter | maximum distance of two vertices |
| polyline | also ´´polygonal chain´´, where the first and last vertex are not connected by a side |
| pseudo range | one of measured ranges differing from the true ranges by a common offset (typical in GNSS) |
| quadric | curve or surface of 2nd order, especially circle, ellipse, hyperbola, parabola, sphere, ellipsoid, hyperboloid, paraboloid |
| quaternion | here: Parameter for the representation of a general spatial rotation, often more useful than Eulerian angles |
| random sample | here: set of continuous random variates (outcomes of a random variable) |
| range | maximum minus minimum of associated values |
| rectified latitude | latitude proportional to length of the meridian arc, such that on the ellipsoid all parallels are equidistant |
| reduced latitude | also ´´parametric latitude´´: latitude of point P′ on circumscribed sphere, quantity shows up in many geodetic formulae |
| redundancy part | fraction of the total redundancy assigned to an observation = degree of controllability by other observations in an adjustment |
| redundancy | also ´´degrees of freedom´´: number of surplus observations |
| refractivity | The refractivity N relates to the refractive index n by N=(n-1)*10^6. |
| residuary misclosure | also ´´residual mismatch´´: given coordinate minus coordinate computed from transformation parameters |
| righthanded | X=thumb, Y=forefinger, Z=middle finger of the RIGHT hand, line of sight onto palm |
| loxodrome | also ´´rhumb line´´: a curve with constant true bearing, i.e. cross-secting all meridianes by the same angle |
| robust estimation | estimation of parameters not grossly falsified by model or data errors like gross errors in the observations |
| shear mapping | also ´´transvection´´: affine mapping of the plane onto itself, which preserves the area of geometric figures, but angles may change |
| skewness | indicates, how symmetrical or non-symmetrical the measurement distribution is. Skewness < 0: skewed to the left, = 0: symmetrical, > 0: skewed to the right |
| slope distance | spatial distance of station and target |
| surface equation | equation, that is fulfilled for points in the surface, but not for others |
| trilateration network | Group of points with some measured distances |
| target height | height of the reflexion point or targeted point above the target marking (zero, if the marking is directly targeted) |
| type I decision error | error that a true null hypothesis is rejected |
| unit vector | vector of length 1 (unit length) |
| vertical index error | deviation of the measured zenith angle from zero, if the telescope is directed to the zenith |
