What is EDM in survey? (Electronic distance measurement) - EngineerSupply

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What is EDM in survey?

Electronic Distance Measurement

Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves. EDM is commonly carried out with digital instruments called theodolites.

EDM instruments are highly reliable and convenient pieces of surveying equipment and can be used to measure distances of up to 100 kilometers. Each piece of EDM equipment available at Engineer Supply provides dependably accurate distance measurements displayed on an easy-to-read digital screen.

Devices known as total stations share similarities with theodolites and can be used to measure distances as well as angles.



Electronic distance measurement in surveying

Theodolites

A Theodolite is a instrument for measuring both horizontal and vertical angles, as used in triangulation networks. It is a tool used in the surveying and engineering industry, but theodolites have been adapted for other specialized purposes as well. A theodolite consists of a telescope mounted movably within two perpendicular axes, the horizontal or trunnion axis, and the vertical axis. When the telescope is pointed at a desired object, the angle of each of these axes can be measured with great precision, typically on the scale of arcseconds. The measurements are typically recorded by hand as they are not recorded by a computer or data collector.

Total Stations

A total station is an optical instrument used in modern surveying. It is a combination of an electronic theodolite (transit), an electronic distance measuring device (EDM) and software running on an external computer, such as a laptop or data collector.

Learn more about Transits, Theodolites, Total Stations, & levels

Many professionals depend on accurate measurements. Whether you are an engineer, surveyor, designer, architect, realtor, contractor, construction worker, estimator, or in another profession you know that you could lose business due to incorrect measurements. There are so many methods and tools available for measuring how do you know which tool to purchase for your measuring needs?

Read this brief guide on selecting the best measuring tool: How to measure almost anything

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Frequently Asked Questions

How does electronic distance measurement work?

Electronic distance measurement (EDM) is a way of determining the length between two points by looking a phase changes that occur as electronic energy waves, which travel from one end of a straight line to the other. But when large variations occur in the terrain or when there's a great deal of obstruction, this method isn’t as effective. So, this method of measurement is avoided in difficult terrain.

What are the types of EDM instruments?

Here are the three types of instruments that are used for electronic distance measurement, which are based on the methods being used:
  • Microwave Instruments — Also called tellurometers, these instruments use microwaves. And they have been around since the 1950’s.

  • Infrared Wave Instruments — Uses prism reflectors that pick up amplitude modulated infrared waves at the end of a line.

  • Visible Light Wave Instruments — Uses modulated light waves to measure up to a specific range.

If you’re looking for a place to buy a broad range of theodolites, total stations, or other tools used for electronic distance measurement, be sure to look at what we have at Engineering Supply.

How does a total station measure distance?

Total stations use the principle of a theodolite and combine it with electronic distance measurement. They also come with a microprocessor and electronic data collector, which is combined with a storage system. Like theodolites, they can be used to measure the sloping distance of certain objects from the instrument, as well as horizontal and vertical angles. Once the data has been collected, it can be uploaded to a computer or laptop for further processing.

Does a transit measure distance?

A transit is a telescope that moves around horizontal and vertical axes, and it’s used to measure angles. The readings will allow you to map a specific site by measuring the position of all of its features, which you can do with a great deal of precision.

How do I measure dimensions?

Three-dimensional measurement is similar to measuring in two dimensions. But in 3-D, the boundaries of a solid object are called the surface area and not the perimeter (which is measured in square inches or feet). The volume refers to the space that it occupies, which is measured in cubic inches or feet. To measure a specific dimension (whether it’s length, width, or height), simply measure any side of a specific surface. If you need to measure two or three dimensions, you’ll need to measure the distance of each side that relates to that specific property.
If you’re looking for a place that has a broad selection of total stations, theodolites, or other electronic distance measurement tools, be sure to look at what we have at Engineering Supply.



Best Smart Levels

David White LT8-300P 26x Transit Level with Optical Plummet

best smart levels 2021 PI-46-D8871

If you’re looking for the best smart level on the market, the David White LT8-300P 26x Transit Level with Optical Plummet is certainly a contender. This unit boasts features such as the following:
  • Range up to 400 ft.
  • Thread size of 5/8 x 11
  • Leveling accuracy of +/- 3/16-in. at 150-ft.
  • Hard carrying case included
This is one of the best builders levels on the market, and its 2 Year manufacturers limited warranty ensures that it will last.

ZIPLEVEL Pro-2000 High Precision Altimeter

best smart levels 2021-PI-ZIPLEVEL-Pro-2000



The ZIPLEVEL Pro-2000 High Precision Altimeter is another one of the best builders levels available, with several features that make it stand out:
  • Average, minimum, or maximum record reading
  • Range of up to 12 meter rod or 6 meter tripod
  • Automatic shut off after four minutes to save battery
  • Internal precision of 0.05” and 0.005” in HP
This smart level is designed to measure any elevation or distance, and its rugged build make it perfect for everyday use on job sites.

Topcon 32x Automatic Level AT-B2

best smart levels 2021-PI-2110220B0

Of all the auto levels on the market, the Topcon 32x Automatic Level AT-B2 stands out for its IPx6 rating and powerful ATB2 viewer. Some of its other features include:

  • 9 inch focusing range
  • +15 arc-minutes range
  • .3 arc-second accuracy
  • 2-speed focusing knob
These details make this one of the most precise levels available. When efficiency and accuracy matter, Topcon gets the job done.

David White LT8-300LP Universal Level-Transit with Laser Plummet

The only thing better than David White builders levels is a builders level that comes with a laser plummet, too. The LT8-300LP is a two-in-one wonder, and offers these features, too:
  • Class 2M laser plummet
  • Thread size of 5/8 x 11
  • Range up to 400 ft.
  • At 150 ft., +3/16 in. accuracy
The unit also includes Stadia and comes with a 2 year manufacturers limited warranty.

Sokkia B20 32X Automatic Level

best smart levels 2021-PI-2110120B0

Durability meets precision in the Sokkia B20 32X Automatic Level. With its magnetic damping system and two-speed focus knob, it’s designed for performance. These features add to its appeal:

  • Easy to see stadia lines
  • Quick setup
  • Automatic compensator
  • 20cm focus distance
If you need a unit that’s resistant to dust, shock, and vibration, this is one of the best auto levels you can choose. Its compact design and superior ruggedness is perfect for construction sites.



Best Rotary Laser Levels

#1: Topcon RL-200 2S Dual Slope Rotary Laser Level Standard Package

best rotary laser levels for construction PI314920722

This dual-slope rotary laser level kit from Topcon is great for exterior applications. In addition to the RL-200 2S Rotary Laser Level, it also comes with the following items:

  • Dry battery kit.
  • LS-80L laser detector with the Holder 6 rod clamp.
  • Hard carrying case.
  • Dry battery kit.
It also has the following specifications:
  • Red laser beam.
  • An operating range of a 3,600-foot diameter with a laser detector.
  • An accuracy of 3/64 of an inch per 100 feet.
  • Rotation speeds of 300, 600, or 900 RPM.
  • Self-leveling.
  • An IP66 Rating for protection against dust and heavy water spray.
Be sure to pick yours up at Engineer Supply today!

#2: Bosch REVOLVE2000 Self-Leveling Horizontal and Vertical Rotary Laser Kit

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This rotary laser level kit is a comprehensive solution to a number of outdoor and indoor leveling applications. The manual dual-slope feature allows you to adjust the slope angle of the rotary laser level on both the X and Y axes. It also comes with a hard carrying case that can hold all the accessories included with this kit. The device has an accuracy of 1/16 of an inch for every 100 feet, which goes up to 2,000 feet if you use the included receiver.

#3: Leica Rugby 640 Series Rotary Laser Package

best rotary laser levels for construction PI-rugby-640

This rotary laser level by Leica Geosystems is an expansion of the company’s broad portfolio of rotating lasers. It’s the best rotary laser level for getting a professional solution with a good price-to-quality ratio, because it will allow you to quickly level and align what you need to build on a construction project while eliminating costly errors.

#4: Johnson Level 99-027K - Self-Leveling Rotary Laser System

best rotary laser levels for construction PI-99-027K

This rotary laser level has a number of useful features, which can include but may not be limited to:

  • A 2,000-foot working diameter (which is over 72 acres).
  • One-person operation.
  • Dust-proof, wash-down rated housing.
  • A 90-degree split beam.
  • Manual leveling along a vertical plane.
  • Visual and audible alarms when you’re beyond its leveling range.
  • Locking compensator that protects the pendulum during transport.
The device also has a 3-year manufacturer’s warranty and has a 1/8-inch accuracy for every 100 feet.

#5: Topcon RL-SV2S Multi-Purpose Rotary Laser Level Standard Package

best rotary laser levels for construction PI313990752

This is the best rotary laser level for horizontal, multi-slope, and vertical applications. This rotary laser level kit comes with the following items:

  • Dry battery kit.
  • LS-80L laser detector with the Holder 6 rod clamp.
  • RC-60 remote control.
  • Hard carrying case.
The red laser beam has an operating range of 800 meters in diameter with a laser detector, and it has an accuracy of 1/16 of an inch for every 100 feet. Be sure to pick yours up at Engineer Supply.



Best Laser Levels

#1: Topcon RL-200 2S Dual Slope Rotary Laser Level Pro Package

best laser levels PI 314920782 This laser level is perfect for doing exterior work, and it comes with the following accessories:

  • Rechargeable battery kit.
  • LS-100D laser detector with the Holder 6 rod clamp.
  • RC-400 remote control.
  • Hard carrying case.
The unit itself has the following specifications:
  • Red laser beam.
  • 2 AA batteries as a power supply.
  • Low battery indicator.
  • IP66 Rating.
If you’re looking for the best laser level for your specific needs, be sure to pick yours up at Engineer Supply today!

#2: Topcon RL-H5A DB Alkaline Horizontal Laser Level with LS-80L Receiver

best laser levels PI 1021200 07 This laser level and receiver has the following features:

  • Operating range of up 800 meters.
  • Smart long-range receiver.
  • Rotation speed of 600 RPM.
  • Simple and intuitive manual slope capability.
  • Horizontal accuracy of up to 10 arc seconds.
  • Self-leveling range of up to 5 degrees.
  • Up to 100 hours of battery life.
  • IP66 Rating for protection against dust, sudden showers, and torrential rainfall.
If you’re looking for the best laser level for establishing a horizontal line reference with an incredible degree of accuracy, be sure to pick yours up at Engineer Supply today!

#3: Topcon RL-SV2S Multi-Purpose Rotary Laser Level Pro Package

best laser levels PI 313990772 This Topcon laser level package is great for horizontal, multi-slope, and vertical applications. It also includes the following accessories:

  • Rechargeable battery kit.
  • LS-100D laser detector with the Holder 6 rod clamp.
  • RC-60 remote control.
  • Hard carrying case.
The tool itself has the following specifications:
  • Red laser beam.
  • Operating range of 800 meters in diameter with a laser detector.
  • Accuracy of 1/16 of an inch for every 100 feet.
  • 300/600 RPM rotation speed.
  • IP66 Rating for protection against dust and heavy jet spray.
If you’re looking for one of the best laser levels for a number of construction applications, be sure pick yours up at Engineer Supply today!

#4: Leica 810945 - Rugby 610 Series Rotary Laser Level

best laser levels PI Leica 810945 Like many other laser levels in this series, this tool is a professional solution with an excellent balance of quality and price. It will allow you to perform quick leveling and alignments for general construction and interior applications. Its housing is extremely durable, so it can perform according to the highest standard in even the harshest of job conditions. It will also work with all Leica Rod Eye Receivers, which will extend its working range up to 2,000 feet (600 meters).

#5: Leica 790363 - Rugby 640 Series Rotary Laser Level

best laser levels PI 790363 Like many other models within this series, this is the best laser level for someone who needs a professional solution with an excellent price-to-quality ratio. With this tool, you’ll be able to do any kind of construction job that requires quick leveling and aligning while eliminating costly errors, rework, and downtime. Because of its rugged housing that’s both dust and water proof, this laser level is built for the construction site. It will perform according to the highest standards in all kinds of job conditions, which is why this series of laser levels is perfect for any construction professional.

#6: Johnson Level Self-Leveling Rotary Laser Level with GreenBrite Technology

best laser levels PI 40 6543 This dual-slope rotary laser level with Greenbrite Technology is the perfect tool for indoor construction projects. It’s a great tool for contractors, finish carpenters, and builders because of the visibility and accuracy it provides. The electronic self-leveling will work on both the horizontal and vertical planes. And because of its green laser beam, it will be 400% more visible than a red-beam laser level (which will make leveling tasks faster and more accurate).

It’s the best laser level for a number of indoor applications, which can include but may not be limited to:

  • The layout of interior walls.
  • Checking door and window height.
  • Installing acoustical and drop ceilings.
  • Developing a layout for warehouse racking.
  • Room additions.
  • Drywall installations.
Be sure to pick yours up at Engineer Supply today!

#7: Johnson Level Self-Leveling Rotary Laser Level

best laser levels PI 40 6515 This self-leveling rotary laser level has a locking mechanism that protects the inner pendulum while it’s being transported from one place to another. It also has visual and audible alarms when it goes beyond its leveling range. The unit is powered by four AA batteries, and it comes with tinted glasses as well as a soft-sided carrying case. The laser level also has the following specifications:

  • Pendulum self-leveling method.
  • Red Class IIIa laser beam.
  • Accuracy of 1/8 of an inch for every 50 feet.
  • Interior range of up to 200 feet in diameter (depending on lighting conditions).
  • Exterior range of up to 800 feet in diameter with a detector.
  • Self-leveling range of up to 3 degrees.
  • Approximately 20 hours of battery life with a rechargeable battery pack.
  • Approximately 24 hours of battery life with alkaline batteries.
If you’re looking for one of the best laser levels on the market, be sure to pick yours up at Engineer Supply.

#8: Futtura LT-850 - Self-Leveling Single Slope Rotary Laser

best laser levels PI Futtura LT 850 This self-leveling single-slope laser is as rugged, reliable, and accurate as it is affordable. And it’s the best laser level for any kind of level or sloped applications. This tool comes with a number of features, which include:

  • Fully automatic self-leveling.
  • Height of Instrument (HI) alert.
  • Operating radius of 2,000 feet.
  • Machine Control Compatible.
  • Accuracy of 10 arc seconds.
It also comes with a standard CR3 Laser Detector, so be sure to pick yours up at Engineer Supply.

#9: Leica 790381 - Rugby 680 Series Rotary Laser Level

best laser levels PI 790381 Like all other laser levels in the Rugby Series, this tool is the perfect professional solution for someone who is looking for a good balance of quality and price. Not only will it allow you to perform quick level operations in general construction and interior applications, but it will also help you to eliminate costly errors. Because of its rugged housing, this tool is built for the construction site. It can perform at the highest level in even the worst job conditions. So if you’re looking for the best laser level for your next construction project, be sure to pick yours up at Engineer Supply.

#10: Johnson Level Electronic Self Leveling Horizontal & Vertical Rotary Laser Level Kit

best laser levels PI 40 6543 This laser level has a vertical mount and is great for both indoor and outdoor construction applications. Carpenters, plumbers, and electricians will love using this tool, because it’s as versatile as it is accurate. The self-leveling mechanism will work on both the horizontal and vertical planes. It can also be useful in the following applications:

  • Leveling.
  • Checking cut and fill.
  • Setting foundations and footings.
  • Septic tank and basement excavations.
  • Acoustical ceiling and drywall installations.
  • Aligning and plumbing walls.
  • Contour framing.
If you’re looking for the best laser level for your specific needs, be sure to pick yours up at Engineer Supply.



Best Total Stations

#1: Leica iCON 5-Second iCB70 Manual Construction Total Station

Best total stations leica-868588

Featuring mobile data capability, this Leica total station will let you transfer construction data between the office and the instrument. This will always keep your project progress and plans up to date, which will make sure you don’t miss any changes in the design. The device is simple and easy to master, so you can finish your projects more efficiently and with minimal training. You can analyze layout points both quickly and accurately, even on complex structures. You can also make fast and accurate as-built measurements, do volume calculations on-site, and work with digital design data (including fully rendered models in IFC format).

#2: GeoMax Zoom90 Series Robotic Total Station Package

Best total stations geoMax-6010321

With this total station, you can minimize the amount of time it takes to perform any survey task, while maximizing your performance and accuracy on the job site. This total station for surveying is the ultimate one-man system with the following features:

  • Up to 20% more automation performance.
  • Extended reflectorless measurement capability.
  • STReAM 360.
  • AccXess technologies.
  • Windows CE open connectivity.
It will scan the entire working area in seconds, so you can find your target quickly. Once it’s locked, the instrument will continue to aim at the target (even if it’s moving). It will also aim accurately at any prism without having to look through the telescope, and measurements are performed automatically with a great deal of dependability.

#3: Leica iCON 5-Second iCB50 Manual Construction Total Station

Best total stations leica-868584

This Leica total station will allow you to go digital, so it’s leading the way to the no-strings and no-tapes approach for a construction project. It’s easy to learn, so you can finish your projects more efficiently and with very little training. This total station will allow you to perform a variety of tasks, which include but may not be limited to:

  • Evaluating layout points and lines quickly and accurately.
  • Evaluating complex structures easily.
  • Quickly performing verticality checks on formwork and structures.
  • Completing fast and accurate as-built measurements.
  • Working with digital design data (including fully rendered models in IFC format).
If you’re looking for one of the best total stations for construction and surveying applications, be sure to pick yours up at Engineer Supply.
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