Dec 2017

Tunnel Vision

Elon Musk envisions a highspeed global transport system consisting of subterranean tunnels bored through the earth within which passenger pods would speed. The bajillionaire entrepreneur formed a new company, Boring Engineering, to carve a prototype tunnel as a proof of concept. After careful site considerations, Boring Engineering’s boring engineers decided to run the tunnel from just outside Las Vegas, Nevada, to Timm’s Hill in northern Wisconsin (think what it could mean for the tourist industry up Nort’). Specifically, the center position of each tunnel endpoint was set at:


NAD 83 (2007) Position



Tunnel End



Las Vegas (LV)

36°09’00.200” N

114°51’43.750” W

1550 ft

Timm’s Hill (TH)

45°27’03.180” N

90°11’43.430” W

1950 ft

When Mr. Musk asked for prototype’s estimated cost per kilometer, the boring engineers immediately realized that while they were capable of designing a tunnel, they really had no idea how to figure out its length until after it was completed. They put their heads together and after a boring discussion, decided to hire you, a surveyor, to help resolve their dilemma. Your mission is to determine (to 10 meters) the shortest distance between the prototype tunnel’s ends.


The spread in the submitted answers was 214 meters which in an ~2,300,000 m distance was only 0.0089%. The difference can be attributed to the ellipsoid heights solvers computed at each point. These varied by a few centimeters, which goes to show the effect small variations can have on long distances. Ahh, the days of 100 ft tapes....

S D B Total Name      Date      Comments
6 10 3 19 Glen Schaefer 22 Dec Distance = 2,298,451 m
6 8 3 17 Larry Schmit 23 Dec Distance = 2,298,665 m
6 6 3 15 Ryan Frisque 02 Jan Distance = 2,298,461 m
4 4 5 13 Norm Hanson 24 Jan Manual computations, but used a sphere and had a math error threwing off his distance.
6 4 3 13 Dave Tlusty 02 Feb Distance = 2,298,462 m

updated 24 Mar 2018