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How Do I
Level this Thing?!??
Ever
step up to the tripod and said to your self,
“oh boy … how do I level this thing again?”
The
answer might well depending on who you ask and what
their profession is, as some might say there is only ONE way to
correctly level the total station.
We
offer here one simple solution on how many of us are accomplishing this
necessary and all-important task in relative ease.
We must
first appreciate the fact that “accuracy rules!” and that
there is no compromise to precise locations of forensic evidence
discovered at the scene.
Most
recommended electronic total stations are equipped with either a single
or double-axis compensator and will not operate
(take distance measurements) unless the Instrument is level to within the
manufacturers specifications.
Users are encouraged to refer to Instrument manufacturer manuals for these
specific configurations.
Most
total stations are also equipped with two external leveling bubbles.
One just atop the screen (Sokkia- horizontal, spirit
level; Leica- circular bulls eye bubble), and one on the
tribrach (bulls eye bubble).

But
back to our recommended “simple solution” for this task!
After
choosing the R.P./Instruments location, spread the three-tripod legs
sufficiently (some recommend a 60-deg.spread) to provide for a good, stable
Instrument platform. Place the Instrument on the tripod’s “faceplate” and
tighten the beneath hand-screw sufficiently firm to prevent any
incidental Instrument free-rotation.
Clue:
Position the tribrachs’ bulls eye bubble closest to you. If
using a “rotating tripod bracket” as seen here, position this first on the
‘faceplate’ then mount the Instrument on top.

You
have undoubtedly noticed on the Instruments lower portion, called the
Tribrach (seen here), three (3) knobs. These knobs
when used independently or together affect a change to the “tilt” or
“pitch” of the Instruments structure itself.

You
should note as well that each knob shaft has a neutral or “common” setting
somehow scribed or otherwise noted on the shaft. This is essentially the
“midpoint” for knowing the half-way motion UP or DOWN.
-
Step 1-
Set all three knobs to the midpoint, neutral or “common” setting
position.

-
Step 2-
Stand squarely between any two sets of tripod legs with Instrument
screen facing you.
-
Step 3-
Using your RIGHT HAND, turn it palm down and
place on the tripod leg at point where it telescopes ~ see next
picture. Use LEFT HAND to unlock tripod leg motion and, while watching
the bubble on the tribrach, slide/telescope up or down the tripod leg.

When bubble at either the
(imaginary) 12 o’clock or 6 o’clock position (see below
diagram), lock down the tripod leg motion.

-
Step 4-
Move either to your Left or to your Right,
between another two sets of tripod legs, and repeat Step 3 above.
When finished, stay positioned here for a moment.
-
Step 5-
Now, simply rotate the
leveling knob directly in front of you in one direction or the other, to
effect the ‘tilt’ of the bubble, placing it exactly in the center
position.
If however the
bubble appears to slide left or right towards the outside the center ring,
use the two ‘distant’ leveling knobs in concert with one another,
rotating them together in opposite directions, to effect a ‘pitch’ of
the Instrument forcing the bubble towards the center leveling ring.

If your
instrument is equipped with a laser plummet (shown above) and once
the Instrument is leveled, the precise R.P. location should be marked or
otherwise noted.
Once
you have leveled the Instrument, it is then time to Zero-SET the
Instrument towards a northerly, compass direction, a topic covered
elsewhere.

It is
fair to note that so long as the Instrument is leveled within a reasonable
time ~ that it is leveled to the extent that it permits distance
measurements, no matter the procedure to get it level, you should be
ready to commence your scene diagramming efforts. |