FORMULA SHELF
6 of 370
The arithmetic behind the work: what to measure, what to type in, and what the answer comes out as. Every formula says what the symbols mean and gives a worked example, so you can check it against a job you have already done.
SHELVES
Surveying
6 formulas
The shoelace method for an irregular field boundary from surveyed coordinates.
A four-point paddock can be computed directly from its corners.
Placing a contour line between two surveyed levels on a plan.
Levels 8.2 and 9.0 m at 10 m apart: the 8.5 m contour is 3.75 m from the low point.
Turning level readings into ground heights for drainage, foundations and earthworks.
RL 10 + backsight 1.5 gives HI 11.5; foresight 2.0 gives RL 9.5.
Converting a compass bearing to a map or grid bearing. Declination changes with place and year.
Magnetic 30 degrees with 5 degrees east declination is true 35 degrees.
More accurate earthwork volumes than end-area averaging, especially on long cuttings.
End areas 10 and 14 m2 with a 12 m2 mid over 20 m = 240 m3.
Convenience only. Double-check the result against the worked example or a second method before you use it.
Converting a distance measured along a slope to the true horizontal distance.
100 m at 10 degrees corrects by 1.52 m.
Convenience only. Double-check the result against the worked example or a second method before you use it.
SOURCES & PROVENANCE
1 listed
This page is an AI-organised index. The label means the grouping and cross-links were compiled with AI; the information itself comes from the public-domain books, reports and manuals listed below. Open any source to read the local copy or follow the link to the original publication.