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,
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