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benchmarks and Lebanon points are of
course not the only visible mapping
feature still available today
triangulation points are of course the
other
unless we've all come across a blast and
all design some of them have more
significant historical interest in
others
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so what exactly are two points then only
for three concrete blocks located at
high point within a certain area used by
the Ordnance Survey to map the entire
country
the idea being you have at least two
others in plain sight you play sad
advice in here measure the angles
between the two and you could
triangulate the whole country well not
the whole country with these two but you
get the idea
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this was a cure across the whole of the
country to within 20 meters
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this however order your three
millimeters in the form that we know
them today triangulation points were
built from 1935 onwards and they were
built to aid the real triangulation of
Great Britain which of course implies
there was triangulation before this and
of course there was the principle
triangulation of Great Britain which
took place between 1791 and 1853 which
brings us nicely to this trick point
here so have a look at Beacon Hill or
any old map which predates the retrying
Gatien of Great Britain and lost this
concrete structure and you'll see the
map states gun the end of base then this
point here contained just that the
upturned muzzle of a cannon stuck out
the ground and in Matt in terms in this
country that was extremely significant
why well because if you walk in the
south of this point we're right about
seven miles and stand in a pig field
just north of Salisbury you know just
walked along what was one of two
original baselines for the original
principle triangulation
the other one can be found in hands
though it's unknown whether the cannon
still survives here today but I'd like
to believe it does why not turn muzzle
cannon well possibly because artillery
man
Williams much was one of three they were
tasked to undertake the mapping
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Williams smudge and his colleagues would
eventually map there were 300 of his
initial triangulation points across the
UK and that is why there is a Canon
placed just under the ground 200 yards
north of the freer through James bring