The concepts involved in calculating the coordinates of a point observed from a traverse station after backsighting on another traverse station are covered. This point is often called a sideshot. We then expand the concepts to cover the situation when the coordinates of the sideshot point are known, to determine the angle to be “turned” and the distance to be measured (i.e. the “stake-out” data) after backsighting a point whose coordinates are known. We then move on to the concept of determining the coordinates of a point on a line such as the midpoint or “quarter points” using the method of proportioning the ∆ northings and ∆ eastings. We then expand this concept to apply the same proportioning concepts to locate points on a line to compensate for the discrepancy between a distance shown on a map and the distance actually measured. We finally work an example quite common in boundary-related surveying where we relate a proportional dimension in an older or original survey to a line measured today. Running time mm minutes.
You will learn…
- How to break down and analyze the geometry of a sideshot problem, whether it is to determine the coordinates of the sideshot point, or to determine the “stake-out data” of a point whose coordinate is known
- How to then perform the mathematical operations to arrive at the desired result
- How, given the coordinates of the endpoints determine the coordinates of the midpoint or any other proportional location (midpoint being at a proportion of one-half)
- How to extend the proportioning concept to the classic problem of needing to determine the location of a point on the line with today’s technology, but given dimensions from an original or previous survey with clear discrepancies in the measurement values compared to today’s measurement.
