The dictionary contains words relevant to cave survey. Common caving terms, such as room, passage, pit, cave, rope, etc. are to be searched in the general Caver's Multi-Lingual Dictionary . The dictionary is alphabetically ordered on the english terms. Red coloured words are terms defined elsewhere in the dictionary. A measurement is more accurate the littler systematic error it is affected by.
Calibration helps in improving accuracy .
The angle measured clockwise that a line makes with the north line. True, magnetic and grid bearings are measured respectively from true , magnetic and grid north . The usual instrument to measure bearings is the compass . The evaluation of the systematic error of an instrument . On a compass , the normal calibration procedure includes also the declination.