Written by JOHN holushayml 1984, this is a digital version of an article from The Times Print Archive, before it starts online in 1996.
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The application of modern electronic technology has completely changed the era of Detroit.
Honor process for measurement and measurement.
Until the changes of recent years, surveyors basically followed the same techniques used by George Washington in the early 17th-century investigation of Northern Virginia for Lord ferfax.
Once the length of the baseline and the angle from both ends of the baseline to that point are measured, the position of the remote point can be fixed by triangular measurement.
Once the second point is determined, other points can be determined until the relevant area is correctly recorded.
The chain used in the Washington era to measure the ground distance is replaced by metal tape, when the chain is in use, the metal tape does not grow as long as the chain, more accurate optical equipment can let the surveyor see farther, but the basic principles of the system remain the same.
However, in recent years, the introduction of electronic distance measurement, that is, electronic distance measurement. D. M.
Instruments with Microprocessor computing power provide surveyors with faster methods of measuring distance and determining location.
They largely replaced the tables of pairs and the detailed calculation time required to produce the survey results before.
"Now, if we want to know where the 'A' point is, we will set up a reflector to send a signal from the 'B' point and read the distance directly," Eugene a said . ".
Greenson, professor of civil engineering at the University of Michigan.
"You don't have to do all the calculations anymore.
'Advertisement' E. D. M.
"The device could be very helpful," said Rajendra K . ".
Aggarwala is a surveying and mapping specialist at the University of Michigan.
"You can reduce manpower by using two methods
Composed of four crew members, you work 30 to 40% faster depending on the mission.
"In order to find the position of a point, the measuring device sends out a beam of electrons that can be microwave, laser, or light outside the visible range, which bounces from the reflector placed back on the point of the instrument.
The distance can be determined by measuring the time the signal reaches the reflector and returns.
Since the speed of light passing through the atmosphere is slightly different from the atmospheric factor, the correction is entered and included in the final reading. Most shorter-
Range instruments use diodes that emit infrared light and can use a distance of two to three miles.
They are accurate to 5mm in a short distance and 15mm in a maximum range.
Fees range from $4,000 to $10,000.
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Because these instruments have filters that only allow the reception of transmitted light, they can be used in direct sunlight without interference.
The electronic measurement of distance was originally developed from World War II radar technology, using microwave to measure the distance of up to 30 miles.
However, because these instruments are bulky and expensive, they are still impractical for most surveyors and are used mainly by organizations that do large measurements
Make a scale map.
However, the shrinking size of electronic devices and the emergence of cheap microprocessor technology have enabled electronic distance measurement to be applied locally. Nikon Inc.
The latest one uses an infrared beam to measure a mile, weighing only four and a half pounds.
The instruments also address the problem of how to measure across rivers, busy highways and inaccessible lands where the use of tape is not practical.
Electronic measurement technology is still developing rapidly.
Paul Hauser, vice president of Keuffel & Esser, said, "The focus now is on the general station," and his slide rule business was eliminated by the development of the handTake a calculator
The company is one of more than a dozen marketing electronic measuring devices in the country.
"With a terminal, you can do all the measurements and store the data in the instrument on the spot," Mr. Hauler said.
"Then, when you go back to your home base, you just dump it all into your computer and it will automatically chart for you.
He said that in addition to the increase in time, such a system eliminates errors that inevitably occur when data is transferred from a live notebook to a drawing board.
Professor Aggarwala said he expected that electronic equipment would completely replace traditional tape and transit measurement systems in the near future.
I think the tape will continue to be used, he said.
On the one hand, the tape is more accurate in a short distance.
"A version of this article was printed on page D00002 of the National edition on April 12, 1984, with the title: technology;
Land Survey of electronic products.