Surveying is arguably one of the oldest professions on earth.
Since the rise of the earliest civilisations on earth people have
required surveyors to measure land and set out construction. Today
as people search for new and sustainable ways to manage the
resources of the planet, surveyors continue to be found at the
forefront of development whether on land, at sea, above or beneath
the Earth's surface.
This is the second in a series of caches about the profession of
surveying. The caches are intended to get progressively harder as
we learn about surveying. The first is Surveying 101. This second
cache is a simple puzzle cache about some of the equipment used by
New Zealand surveyors.
Do not go to the listed coordinates as they are false
coordinates. The cache is located at S 43 AB CDE E 172 FG HIJ
Where:
In the very earliest of New Zealand surveys, surveyors used
Plane Tables to map the geography. The plane table was a large flat
surface mounted on tripod legs, the table could be precisely
levelled with bubble levels over a specific point. An instrument
was used with the plane table to map the land, which consisted of a
telescope and a plane rule. The instrument was used to sight lines
to distant objects and the distance to them could be calculated by
intersecting the lines from two or more sight lines from other
known points. D = Number of letters in the instrument name.
Early surveyors then made use of Transit Theodolites and Gunters
Chains. Transit Theodolites used precisely engraved circles and
vernier scales to read angles to a second of arc. The transit
theodolites were used to measure angles in the early surveys. One
of the more famous makers was ???? and Simms. B = Value of the 6th
letter.
The Gunthers Chain is a chain of exactly 100 links the
“chain” was a specific length and this brings about
many of the imperial land measures such as a furlong and the acre.
More about this at a later date. The Gunters Chain was used to
measure distances in the early surveys. Using the theodolite to
keep it straight the chain was layed out towards the object being
measured to and the number of links to the object was recorded. For
longer measurements the end of the chain was marked, then the chain
was moved to start from the end point with the process repeated
until the object being measured to was reached. The number of
chains and links was then recorded. This process was called
ranging. Surveyors were required to test their chains against a
standard chain held by the government surveyors office. Year the
chain was designed 16A0 Length of chain in feet = YZ Y-A=E Z+A=C
Length of chain in metres = 20.GG68
Following World War 1 optical thedolites were created and the
Steel Band became common for measuring distances. The optical
theodolite used precisely engraved optical circles and optical
micrometers to read angles. Arguably the best known instrument
maker created the T series with the small T1A being the least
accurate the T4 being a high accuracy instrument and the T2
probably being the most common instrument in New Zealand from the
1930’s until the invention of electronic Total Stations in
the 1980’s What was the Makers Name. F= Letters in the makers
name
Steel bands were long lengths of narrow gauge steel band usually
2-3 mm wide and 0.2 to 0.3 mm thick which where marked with brass
studs at specific units. The steel band came in both imperial
(chains and links) and metric (metres) measures The bands would be
held at specific tensions and calibrated for the temperature, and
the slope of the line to calculate the length of lines. Te Papa
holds a Bolt and Sutherland Steel Band in its online collection.
What year does the band date from circa 19W0?. H=W-1
With the advent of Electronic Distance Measurement (EDM) and
computerisation Total Stations became the surveyors measurement
device of choice and are now widely used by surveyors. The total
station incorporates an electronic theodolite and an inbuilt EDM.
The instruments have digital displays and on board data storage.
Name the company that the main optical theodolite maker for F above
has become Number of letters in name = J.
Surveyors have also made use of high precision GPS. One of the
leaders in this field has a research and development office in
Christchurch, NZ. Number of letters in the name = X. (X+1)/2=I
You can check your answers for this puzzle on
Geochecker.com.