Theodolite † a tripod mounted instrument designed to measure
angles in the horizontal or vertical plane.
The theodolite in principle
Measurement † a telescope provides for focal location between
instrument and subject. Position of the scope is defined by an index of
angles. The scale and presentation of angles varies from traditional
micrometer readings to computer compatible crystal displays. Angles
are measured in degrees, minutes and seconds, e.g. 165° 5303000.
Direct reading micrometer scale
Application † at least two sightings are taken and the readings
averaged. After the first sighting, the horizontal plate is rotated
through 180°and the scope also rotated 180°through the vertical
to return the instrument to its original alignment for the second
reading. This process will move the vertical circle from right face
to left face, or vice-versa. It is important to note the readings
against the facing † see below.
Setting Out---Angles