Hi,

There's a nice podcast and small write-up by 99-percent invisible that
talks about a fake town that got added to a map:

http://99percentinvisible.org/episode/mini-stories-volume-2/

Starts at ~10:10. It appears there's a ted-x talk too but I've yet to watch
it.

Cheers,

Sam

On Jul 6, 2017 14:28, "Ralph Corderoy" <ra...@inputplus.co.uk> wrote:

Hi,

In aviation, Voronoi diagrams are superimposed on oceanic plotting
charts to identify the nearest airfield for in-flight diversion as an
aircraft progresses through its flight plan.
https://en.wikipedia.org/wiki/Voronoi_diagram#Engineering

https://en.wikipedia.org/wiki/Zatocoding is a 1940's method of selecting
index cards based on their perimeter having holes, some of which are cut
through.  Rather than H holes representing S subjects in a 1:1 mapping,
it allows S>H by having each subject be indicated by cutting a pattern
of more than one hole.  Some subjects may overlap, giving false
positives, but the probability of this can be adjusted.  The
https://en.wikipedia.org/wiki/Bloom_filter used in programming is
related.

A https://en.wikipedia.org/wiki/Ghost_word is a deliberate error to
catch copyright infringement.  Maps have
https://en.wikipedia.org/wiki/Trap_street.  Both forms of
https://en.wikipedia.org/wiki/Fictitious_entry.

Laser printers watermark printing to identify the individual printer.
https://www.eff.org/pages/list-printers-which-do-or-do-
not-display-tracking-dots
There was a mention of a similar technique for videos to track 4K source
being HD recorded;  anyone know the name?  For audio, there's
https://en.wikipedia.org/wiki/Cinavia

Powers of two in imperial units;  halving and quartering is easy.

    $ units -1v usgallon fluiddram
            usgallon = 1024 fluiddram
    $ set usgallon usquart uspint usgill usfluidounce fluiddram
    $ f=$1; shift
    $ while (($#)); do units -1v $f $1; f=$1; shift; done
            usgallon = 4 usquart
            usquart = 2 uspint
            uspint = 4 usgill
            usgill = 4 usfluidounce
            usfluidounce = 8 fluiddram
    $

Python's Coverage.py can test more than if every statement is executed
at least once.
https://coverage.readthedocs.io/en/coverage-4.4.1/branch.html

Telegu is the third most-widely spoken language in India.  They write in
decimal before the decimal point, and base 4 after.  But they don't
write the point, instead having distinct symbols for 1/4, 1/2, and 3/4,
but for 0 they re-use the symbol from integers.  In 789½¼¾ it's clear
the transition from integer to fraction is after the 9, but 7890½¼¾ is
ambiguous because the point might be either side of the 0.  Their
solution is to have a second set of base-4 symbols, say 0¼½¾ for the
first set, and abcd for the second.  The first set is used for the even
positions, and the second set for the odd ones.  7890½a¾ and 789a½b¾ are
now unambiguous because you can never have `.0', and it throws in a
little bit of error detection against putting the point in the wrong
place.  Though I don't know if that was a happy accident.
https://en.wikipedia.org/wiki/Telugu_script#Numerals

Cheers, Ralph.

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