We begin with the concept of measuring angles with the magnetic compass, really, a calculation from observing directions with it. It includes a bit about parts of the compass and how it is used. Other aspects of the compass including how they were supported in the field, the use of sighting vanes and telescopes, and the function of the vernier and how it was used to set off declination are discussed. The development of the steel circle transit is covered next. The basic components and how they were used are covered, especially, how the upper and lower motions facilitated precise measurement of angles by repetition. The discussion then moves on to the glass circle theodolites and the micrometer systems for reading the circles. Various strategies for improving vertical axis tilt because of its impact on the measurement of angles in the vertical plane are covered. We finally arrive at the various kinds of present-day total stations. We end with a discussion of data reduction of field notes taken by the repeating method and by the direction method. Running time 37 minutes.
You will learn…
- How compasses were used and a little bit about their development
- The basic components of a transit and how it was used
- How the theodolite is similar to and yet different from the transit
- About various types of functionalities provided by various types of total stations
- Reduction of field notes of angle measurement by the repeating and direction methods.
