Posts Tagged ‘3-D mapping’
Unveiled: The Most Detailed 3-D Map of Local Universe Ever Created
The project mapped more than 43,000 galaxies picked from the Two-Micron All-SkySurvey (2MASS), which scanned the entire sky in three near-infrared wavelengths. But 2MASS alone offered an incomplete picture. To achieve the third dimension, astronomers needed to know not only how galaxies relate spatially on a flat map, but how far away they are from Earth and each other. So the 2MASS Redshift Survey began measuring the galaxies’ redshifts, one by one, using two telescopes in Arizona and Chile.
Redshifting is the way in which a galaxy’s light is stretched into longer wavelengths by the expansion of the universe. The farther a galaxy is from Earth, the greater its redshift. By analyzing those measurements, the 2MRS was able to achieve that important third dimension, and to produce the map you see above.
But 2MRS isn’t just notable for mapping faraway galaxies. It also made great strides closer to home. Regions nearer the Milky Way tend to be difficult to observe, as they are obscured by the dust and gas in our own galaxy. The near-infrared wavelengths employed by 2MASS are better at penetrating this dust, giving us a better look at our own galactic neighborhood.
A higher res version of the pic is available .
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Tandem Pair of German Orbital Imaging Satellites Will Create Sharpest-Ever 3-D Map of Earth
Germany's TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) successfully separated from its carrier rocket and was put into a polar orbit slightly inclined to the one it's sister satellite, TerraSAR-X. Together, the two will dance an intricate orbital tango as TanDEM-X flies a tight pattern around TerraSAR at an altitude of about 320 miles above the Earth. It's the first time two satellites will orbit in such a tight formation for such an extended period.
By bouncing microwaves pulses off the planet's surface and timing the return signals, the satellites' highly sensitive instruments will be able to map the entire land surface of the earth in extreme detail. TerraSAR-X alone has been able to map the surface to within an accuracy of about 30 feet, but with TanDEM-X at its side that accuracy should be pared down to within six-and-a-half feet.
A 3-D map that accurate will have vast military, research, civil, and commercial applications, ranging from tighter low-flying routes for strategic aircraft to better-organized search and rescue plans during earthquakes to more accurate city planning and land use assessments. Further, while other 3-D topographic maps have been piecemeal efforts, the TanDEM-X mission will be one single, cohesive map of the entire surface of the planet. With the satellites both in orbit, work now is focusing on upping the resolution so allow the rendering of detailed, massive images from the data collected from a single pass overhead.
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Laser Scanning Flyovers of NYC Will Yield Most Accurate 3-D Map
The early a.m. flyovers, conducted by a specially equipped Shrike Commander aircraft, will produce the most detailed maps the city has ever known, capturing 3-D images that detail surface terrain and structural elements in unprecedented detail. Current maps -- like the one FEMA uses to determine the city's flood plains -- were composed in the 1980s from aerial photography and surveys.
The new maps will help city planners rezone neighborhoods, determine shifts in population density, identify remaining wetlands, and even figure out which neighborhoods simply need more trees. It will also help the city determine what to do if/when rising sea levels brought on by global warming begin to threaten waterfront areas.
An operator aboard the aircraft operated the LIDAR -- light detection and ranging -- sensor as the pilot made repeated low-flying sweeps over the city at around just 3,500 feet during the second half of April. The laser surveying tech fired laser pulses from the aircraft at the topography below, measuring the time it takes the pulses to bounce back, much as sonar does with sound.
While wetland identification and population density maps will surely excite urban planning types, the solar map is hands-down the most exciting aspect of NYC's new cartographic pursuit. The aerial survey has determined the number of pitched and flat roofs across the city and will allow NYC residents and property owners to go online and see whether their buildings are good candidates for solar panels. That, in turn, could lead to increased adoption of solar tech, making the U.S.'s most densely populated burg even greener. The data is currently being crunched and should generate detailed solar and flood maps by year's end.
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