Can't find a cite for it, but in Alaska I also heard of BLM "tracer bullet triangulation", used in heavily forested areas, where a crew would roughly traverse (compass, cloth tape/pacing?) with assistance from rectified photogrammetry to a computed corner, set up a tripod with a levelling gimbal which had a .357 revolver with remote trigger on it and fire off a white tracer round which was observed by (2-3?) theodolites on control stations on higher ground miles away, all coordinated by radio.?ÿ The observers would compute the triangulation and radio a distance & direction to the computed corner, where the ground crew would reset up for a second shot and set a pipe if it was good to 5-10 feet, etc.
Advantages:
- Ground crew only carried pipes and implements, 1 tripod & no theodolite, no record of their route to the point needed.
- They could get to the next computed corner needed by the easiest route (up a creek, through a meadow) instead of running line.?ÿ Greatly speeds up densifying PLS corners.
- The triangulation guys had an easy life; get to the station, kick back and make only 15 observations max per day.?ÿ I pray they were rotating the ground crew duties so all were equally miserable.
Disadvantages:
- The line was never run, so blazes, chopped line evidence, etc. is forever lost.?ÿ Typical in the Alaskan outback; get the corner in is paramount, so adjoinders have something to hang their hats on.
- Um, shooting incendiary bullets straight up as near as may be could injure ground personnel.
- Um, shooting incendiary bullets into dry tree cover, especially if it's a squib could start a fire.
- If it's windy the math goes awry, any late (above 30?ø)?ÿ observation is greatly affected by altitude and near simultaneous timing near the treetops was optimal, but not achievable without?ÿ
?ÿThe killer was the gun gimbal was only good to 1/2 degree or so errors of 30' or so were inherent if observed if the trace was observed thousands of feet in altitude.?ÿ Does anybody have intel concerning this technique, Googling has not been fruitful.
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Google: tracer triangulation.
First hit: https://archive.amerisurv.com/PDF/TheAmericanSurveyor_Penry-TracerTriangulation_Vol10No4.pdf
Second hit: Jerry Penry discussing the research that went into the article in a 2013 forum post.
https://surveyorconnect.com/community/surveying-geomatics/tracer-triangulation-the-bullets/paged/
Volume 10 Number 4 of American Surveyor has an article by Jerry Penry about this. Jerry defended his work on this forum when questioned by another very famous surveyor whose last name is Wahl.?ÿ
For some reason my phone won't let me copy the links but if you Google "triangulation tracer bullets" you'll find both.
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