Automatic
Levels are used by people whose jobs rely on fast and accurate
measurements. Those include engineers, surveyors, landscaping professionals, and
contractors, as well as deck, pool, and fence builder. Like a standard level, an
automatic one relies on centering a bubble. The
automatic level allows the bubble to be viewed as an erect image
during setup and sighting and is close to set and eliminates the wait for
settling. . An air-dampened compensator prevents magnetic interference. An
internal compensator mechanism automatically removes disparity from the level.
The automatic features cut down on the possibility of human error and maximize
the ease of taking measurements to yield better productivity and
performance.
If you are concerned about how well the level will hold up in inclement
weather, check the rating and durability guarantee. Most automatic levels offer
some protection from humidity, dusts, and vibrations. For those working in rough
conditions, there are options for models with a rugged casing that is designed
to protect the instrument’s functionality, even if it is dropped – both on land
or water. IP57 signifies that the equipment can withstand total immersion in
water and is fully dustproof. Manufacturer warranties also vary. One year is
standard, but some extend to as long as five years.
Generally, automatic
levels are designed to be easily carried and attached to a tripod
for a steady base point. Some include nice conveniences like backlit LCD
displays for easier reads in low light situations, built in memory. Check for
the range, magnification, accuracy, and temperature range that your job
requires. Taking measurement in tight spots or on steep slopes would require the
ability to focus over shorter distances. The cost for automatic levels range
from about $150 to over $2000, depending on the features.
Theodolites
are a key tool for land surveyors and engineers who have to determine
horizontal and vertical angles.
Until technology made it possible to automate measures and calculations,
using a theodolites involved a great deal of manual setup, manipulation, and
math. Here’s how the process is described
The observer looked through the telescope and carefully aligned the vertical
cross-hair with the left-most survey target. The horizontal circle was rotated
so that it read just above zero when the cross-hairs were on this target. The
circle was then locked in place and the direction indicated on the circle was
read and recorded. After this reading was taken, the telescope was rotated
clockwise until the cross-hair was aligned with a second target. This second
direction was read from the circle and recorded. This procedure was repeated
until all targets were observed and recorded. Then, the telescope was rotated
180 degrees around both axes. The same stations were observed again and the
angle values recorded.
This entire procedure was one set of angles.
Consider that all those adjustments had to be observed and recorded for a
single set, and then the surveyor or engineer was still far from done:
The two readings for each target were averaged to help eliminate systematic
errors. The number of sets of angles observed depended on the precision of the
survey work being performed. For first-order survey work, 16 sets were observed
and averaged to determine the final angles. Directions exceeding a specified
value from the mean were rejected and repeated.
Think of going through all those calculation. Now you don’t have to think too
much about it because today’s
theodolites
offer greater ease of use, combined with higher speed and accuracy. The digitial
electronic technology in modern theodolites eliminate the necessity of manual
adjustments and extensive calculation. The optical plummet allows the user to
align instrument directly over a reference point without having to use the old
plumbob method. The key pad is very easy to use. The measurements appear clearly
on the LCD screen within seconds. The accuracy of the angle measurement is
excellent with a range of 2 to 20 seconds, depending on the model.
Select the model that is up to the job for you. That means it has all the
features you need sand will hold up to the condition you will work in, whether
they are dark, dusty, damp or downright wet. Its ranking for holding up to water
and dust is indicated by its IP rating with 66 being the highest available. If
you are going to be working in conditions of low or no light, like underground,
in a tunnel or inside a structure without windows, you would benefit from a
model with a built-in reticle illuminator and backlit LCD, so that you can view
its readings without having to shine a flashlight on it. If you are concerned
about operating cost and downtime, look for features like a rechargeable battery
pack and charger and backup batteries. Theodolites may also include other
convenient options like a sun shade, tool kit, rain cover, drying cloth, plumb
bob and carrying case.
The median price for a theodolite is in the $2000 range, though some advanced
models can top $12,000, and some basic models are available for under $800. More
advanced models use lasers and keep a record of measurements, allowing you to
take repeated or repositioned measurements without stopping to write down the
figures and come up with calculation. The data is saved and managed on a
computer. That eliminate read and write errors and facilitates the data direct
entry into software.
At tiger
supplies we carry all brand theodolites Sokkia, Topcon, Leica,
Spectra Precision, Nikon, Cst Berger, Northwest Instruments, South Survey,