Scientists get a three-dimensional Google Earth on steroids, which can penetrate forest canopies, chart sand dune movement, and more, thanks to radarlike lasers
Unlike traditional satellite images or aerial photos, airborne laser swath mapping (ALSM) creates three-dimensional models of the terrain below....[More]
Modeling the Mountains
Unlike traditional satellite images or aerial photos, airborne laser swath mapping (ALSM) creates three-dimensional models of the terrain below. How does it work? A small plane, equipped with an optical scanner, emits rapid-fire laser pulses (50,000 to 150,000 per second) that are reflected straight down in a zigzag configuration by a moving mirror. Based on the same principle as radar, a specialized detector in the plane picks up rays as they're reflected off of the ground. By clocking the beams' round-trips, the ALSM can calculate the distance to a single point on the ground. The plane's elevation and motion are controlled for by an onboard inertial measurement unit, and global positioning system (GPS) tracking—along with a ground base station—ensure that the precise location of the airplane is recorded at all times. The result: a rich and rapid model of a mountain.
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Josh Roering/University of Oregon/National Center for Airborne Laser Mapping/NSF
Seeing the Forest (Floor) Through the Trees
Even the best areial mapping efforts have had to leave forest floors in the dark because they're generally obscured by the canopy. But ALSM mapping is able to peer through the foliage....[More]
Seeing the Forest (Floor) Through the Trees
Even the best areial mapping efforts have had to leave forest floors in the dark because they're generally obscured by the canopy. But ALSM mapping is able to peer through the foliage. The laser used in most of the mapping equipment has a near-infrared wavelength, which is reflected very well by the chlorophyll in plants. But some of the light pulses do make it between the leaves, to the forest floor and back to the plane's sensors. Computer refinement can be used to filter out all of the waves reflected by vegetation and produce a detailed model of the terrain itself. These new views can detect and map hidden landslides, fault lines and other potential dangers.
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Josh Roering/University of Oregon/National Center for Airborne Laser Mapping/NSF
Following the Flood
In the midst of a flood last June, researchers mapped a large corridor of the Iowa River using ALSM. This image—to which color was added to distinguish water, vegetation, structures and land—provides much more data than a satellite image could....[More]
Following the Flood
In the midst of a flood last June, researchers mapped a large corridor of the Iowa River using ALSM. This image—to which color was added to distinguish water, vegetation, structures and land—provides much more data than a satellite image could. The model shows scientists (within inches) where surging waters are prone to flow and what elevations the water crept to. The resulting information can be helpful to planners, who make decisions about land use and bridge placement, to limit damage from future floods. Any margin of error from the air (which researchers list at about two to six inches—five to 15 cm—in height and eight to 12 inches—20 to 30 cm—in lateral distance) can be reduced to one to two inches (three to five cm) by comparing the airborne data with on-the-ground GPS surveys.
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Witold Krajewsky/University of Iowa/National Center for Airborne Laser Mapping/NSF
Ground Zero
Twelve days after the September 11, 2001, World Trade Center attacks , a team trained in ALSM from the University of Florida and personnel from Optech Inc., (a manufacturer of the equipment) began collecting aerial data of Lower Manhattan ....[More]
Ground Zero
Twelve days after the September 11, 2001, World Trade Center attacks, a team trained in ALSM from the University of Florida and personnel from Optech Inc., (a manufacturer of the equipment) began collecting aerial data of Lower Manhattan. The three-dimensional models they assembled were paired with ground measurements to provide a detailed analysis of the damage. From the three-dimensional models, the group was able to estimate the amount of debris that would need to be removed from the sites as well as locate the safest routes for cranes and other equipment to enter the area to start the work of taking down remaining walls and repairing buildings that were damaged nearby.
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National Center for Airborne Laser Mapping/NSF
Demystifying the Mounds
ALSM is also being used to investigate mysterious Mima Mounds in central California. The California mounds, which resemble clusters in other states and countries, stretch over more than 15 square miles (40 square kilometers)....[More]
Demystifying the Mounds
ALSM is also being used to investigate mysterious Mima Mounds in central California. The California mounds, which resemble clusters in other states and countries, stretch over more than 15 square miles (40 square kilometers). Since the nineteenth century, the origin of such mounds has been contested, with theories that range from Native American burial grounds to seismic activity. In an effort to level the mystery, researchers from the University of California, Berkeley, and Arizona State University in Phoenix have mapped the California mounds and the surrounding terrain (a sample of which is seen here in false color). The contours of the land help them calculate average erosion and soil deposit rates necessary to figure out how much—and how quickly—material would have to move to explain the mounds. ALSM data supports the theory that the mounds were actually created by burrowing pocket gophers.
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Sarah Reed/National Center for Airborne Laser Mapping/NSF
Shifty Sands of Time
White Sands National Monument in New Mexico is the largest expanse of gypsum dunes in the world. The 275 square-mile (700 square-kilometer) area has been a popular tourist destination since it opened as a federally protected site in 1934....[More]
Shifty Sands of Time
White Sands National Monument in New Mexico is the largest expanse of gypsum dunes in the world. The 275 square-mile (700 square-kilometer) area has been a popular tourist destination since it opened as a federally protected site in 1934. But the main attractions are always on the move—some at the rate of 40 feet (12 meters) a year. Even the more stately dunes speckled with anchoring plants creep along little each year. Such amorphous subjects can be tough to track with simple averages and occasional satellite images.
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National Center for Airborne Laser Mapping
Waves of White
Three-dimensional images made with ALSM are able to capture the dune landscape within inches of its actual size and shape. Seen here, a computer-modeled image of the area might resemble a satellite photo , but it's rich in millions of thee-dimensional data points....[More]
Waves of White
Three-dimensional images made with ALSM are able to capture the dune landscape within inches of its actual size and shape. Seen here, a computer-modeled image of the area might resemble a satellite photo, but it's rich in millions of thee-dimensional data points.
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Ryan Ewing/University of Texas/National Center for Airborne Laser Mapping/NSF
Mapping Movement
By comparing two detailed models created at different times, researchers can see in full color precisely how much each dune is moving and in what direction....[More]
Mapping Movement
By comparing two detailed models created at different times, researchers can see in full color precisely how much each dune is moving and in what direction. Tracking the movement of sand can have especially important implications for areas of the globe that are under threat of desertification. Other time-based map comparisons can give scientists a rare and detailed glimpse into changes—both subtle and massive—happening on Earth's surface, and perhaps a better chance of predicting and mitigating natural disasters.
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Ryan Ewing/University of Texas/National Center for Airborne Laser Mapping/NSF
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"Employed by the military, meteorologists, astronomers, conservationists and even automotive engineers, it can spit out three-dimensional models of a distant surface.."
"it can spit out" ? This is one horrible use of English language.
So Can lazer mapping find hidden ancient reins in the amazon rain forest.If so i know at least 20 places in brazil where they may find something intreasting.Can it map the bottom of the ocean and find hidden ships wrecks.Hidden ship wrecks filled with hundread of millions in unclaimed treasure.
Lazer mapping could find hidden ancient reins in the amazon rain forest.If so i know 20 areas where they could find something really intreasting.Lazer mapping could find hidden ship wrecks under the sea.There could be hundreads of millions of dollars in sunken treasure to be found.
ALSM can certainly be used to map ancient ruins hidden under heavy vegetation, but the near infrared light produced by the lasers used on most systems does not penetrate water, so it is not much good for locating ship wrecks. There are ALSM systems that use green lasers that do penetrate water, but generally only to depths of a few tens of meters, even in clear water.
ALSM can certainly be used to find and map ruins of old structures or mounds under dense vegetation, but the near infrared light produced by the lasers used in most systems does not penetrate water and would not be of much good for finding ship wrecks. Systems with lasers that produce green light can penetrate water, but generally less than 100 feet even in relatively clear coastal waters.
ALSM can certainly be used to find and map ancient buildings and mounds under dense vegetation, but the infrared light produced by the lasers most systems does not penetrate water and would not be useful for finding ship wrecks. Systems with green lasers can penetrate water, but generally only to less than 100 feet even in clear coastal water.
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13 Comments
Add Comment"Employed by the military, meteorologists, astronomers, conservationists and even automotive engineers, it can spit out three-dimensional models of a distant surface.."
Reply | Report Abuse | Link to this"it can spit out" ?
This is one horrible use of English language.
Is there value in this technique for finding buried archeologiical sites?
Reply | Report Abuse | Link to thisIs there value in this technique for finding buried archeologiical sites?
Reply | Report Abuse | Link to thisFor that purpose you better shoul use deep soil radar sensors.
Reply | Report Abuse | Link to thisFor that purse you should use deep soil penetratig radar.
Reply | Report Abuse | Link to thisI hear an echo
Reply | Report Abuse | Link to thisMay be it can help to find hidden old cities in the jungle, perhaps mayan and inca's cities.
Reply | Report Abuse | Link to thismay be it can helpto find hidden cities in the jungle,perhaps mayan and inca's cities.
Reply | Report Abuse | Link to thisSo Can lazer mapping find hidden ancient reins in the amazon rain forest.If so i know at least 20 places in brazil where they may find something intreasting.Can it map the bottom of the ocean and find hidden ships wrecks.Hidden ship wrecks filled with hundread of millions in unclaimed treasure.
Reply | Report Abuse | Link to thisLazer mapping could find hidden ancient reins in the amazon rain forest.If so i know 20 areas where they could find something really intreasting.Lazer mapping could find hidden ship wrecks under the sea.There could be hundreads of millions of dollars in sunken treasure to be found.
Reply | Report Abuse | Link to thisALSM can certainly be used to map ancient ruins hidden under heavy vegetation, but the near infrared light produced by the lasers used on most systems does not penetrate water, so it is not much good for locating ship wrecks. There are ALSM systems that use green lasers that do penetrate water, but generally only to depths of a few tens of meters, even in clear water.
Reply | Report Abuse | Link to thisALSM can certainly be used to find and map ruins of old structures or mounds under dense vegetation, but the near infrared light produced by the lasers used in most systems does not penetrate water and would not be of much good for finding ship wrecks. Systems with lasers that produce green light can penetrate water, but generally less than 100 feet even in relatively clear coastal waters.
Reply | Report Abuse | Link to thisALSM can certainly be used to find and map ancient buildings and mounds under dense vegetation, but the infrared light produced by the lasers most systems does not penetrate water and would not be useful for finding ship wrecks. Systems with green lasers can penetrate water, but generally only to less than 100 feet even in clear coastal water.
Reply | Report Abuse | Link to this