2888: US Survey Foot

2024-01-31T21:32:51Z

JonLennox: Point out there is no U.S. territory exactly 8,000 miles from NIST headquarters

{{comic
| number = 2888
| date = January 31, 2024
| title = US Survey Foot
| image = us_survey_foot_2x.png
| imagesize = 740x606px
| noexpand = true
| titletext = Subway refuses to answer my questions about whether it's an International Footlong or a US Survey Footlong. A milligram of sandwich is at stake!
}}

==Explanation==
{{incomplete|Created by a 610 NANOMETER BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic pokes fun at a difference in length of the {{w|Foot_(unit)#U.S._survey_foot|US Survey Foot}} and the {{w|Foot_(unit)|International Foot}}. After {{w|International_yard_and_pound|an international agreement}} in 1959, the foot has been defined to be exactly 0.3048 metres, whilst the US survey foot is defined as 1200/3937 meters and is a bit longer than the international foot. However, the difference between the two is proportionately too small for most purposes, as they only differ by 2 parts per million. At foot-length scales, the difference is a fraction of a millimetre, with longer measures (where the error grows to a notable degree) requiring an already excessive implied precision likely to mismatch its true accuracy. Some engineering or scientific applications ''may'' involve such tolerances, but would be expected to consistently use some more modern standard of measurement to {{w|Mars Climate Orbiter|avoid such confusion}}.

In the fourth panel, Cueball says that [[Black Hat]] is drawing the world 610nm closer to madness, which is about the difference between the two measures. Cueball, outraged, then tells that the {{w|National Institute of Standards and Technology}} has been authorized to capture Black Hat to stop him from using the US survey foot. The joke here is that his coordinates show that he is 8,000 miles away, but since he is using the US survey foot, he is 0.016 miles away from the search team, making the search team unable to find him.

Note – 0.016 miles is about 28.16 yards, or 25.749 metres.

Randall is playing a bit fast-and-loose here. To make this joke work implies a rather absurd situation: that both Black Hat and the searchers would need to have set their devices to measure location ''in reference to'' NIST headquarters and not just use GPS and lat/long. That's where we get the 8,000 miles from to make the joke. So even in the unlikely event that the searchers' phones measure location like this because they're from NIST, it's very unlikely that Black Hat would override his device's in-built GPS to report its location in reference to NIST headquarters – unless he knew that NIST searchers also did this and knew they wouldn't find it suspicious for him to do it too.

The title text references a {{w|Subway (restaurant)#Sandwich_size|2013 lawsuit}} over the length of a "Footlong" sandwich sold by Subway fast food chain. However – in contrast to the issue at stake in that lawsuit – the difference in length between an 'international footlong' sandwich and a 'US survey footlong' sandwich is way below the precision ''or'' accuracy by which sandwiches are usually produced – making it understandable that Subway would not think it necessary to clarify which definition of 'foot' they use for their products.

There is no U.S. territory which is [https://www.mapdevelopers.com/draw-circle-tool.php?circles=%5B%5B12874687.81%2C39.1450494%2C-77.2161307%2C%22%23AAAAAA%22%2C%22%23000000%22%2C0%5D%5D exactly 8,000 miles from NIST headquarters in Gaithersburg, Maryland] (regardless of which foot is used), so it's not clear how the NIST strike team would have jurisdiction over Black Hat. The closest U.S. territory would probably be Cocos Island, Guam, 7923.92 miles away from Gaithersburg; the closest U.S. jurisdiction is probably the U.S. Embassy in Dhaka, Bangladesh, at 8015.14 miles.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Closeup on Cueball.]
:Cueball: We thought it was over. After 60 years of struggle, the US survey foot was dead, deprecated by NIST in 2023.

:[Cueball is shown to be talking to Ponytail, Hairy, and Megan. He has a presentation behind him.]
:Cueball: We thought architects and engineers could rest east, free of the headaches of having two conflicting definitions of the foot that differ by 610 nanometers.
:International foot: 0.304 800 000 m
:US survey foot [crossed over in gray] <span style="color:gray">R.I.P.</span>: 0.304 800 609... m

:[Cueball points at an image of Black Hat]
:Cueball: But I bring dire news:
:Cueball: ''Someone has started using the US survey foot again.''

:[Closeup on Cueball again.]
:Off-panel voice: Why!?
:Cueball: We don't know.
:Cueball: Some people just want to drag the world 610nm closer to madness.

:[Farther view of Cueball only. He clenches a fist.]
:Off-panel voice: What can we do!?
:Cueball: A NIST team is already in the air. We will capture the scofflaw and end this nightmare.

:[Two helicopters flying, with mountains in the background.]

:Caption: 8,000 miles away
:[Two operatives in a forest with "NIST" helmets. One talks on a walkie-talkie.]
:Operative: We've reached the coordinates of the target's device. There's no one here.
:Voice from walkie-talkie: How!?

:Caption: 8,000.016 miles away
:[Black Hat walking elsewhere in the forest, very close by.]
:Black Hat: ♫ ♪

==Trivia==

The number of miles in the last panel was [https://www.explainxkcd.com/wiki/images/archive/5/5f/20240131173446%21us_survey_foot_2x.png originally] 8,000.014, but was changed to 8,000.016. The latter matches the 2 ppm difference between the international foot and the US survey foot.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Black Hat]]
[[Category:Characters with hats]]
[[Category:Geography]]
[[Category:Food]]

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2888: US Survey Foot