Tag Archives: mapping

Ancient Cambodian City Revealed in Laser Scan

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Airborne laser scanning has revealed the remnants of a vast urban structure in the vicinity of Angkor Wat, a famous temple in Cambodia. The study, which will be published soon in the journal PNAS, follows earlier research that showed Angkor Wat to have been one of the world’s most complex preindustrial cities.

Light Detection and Ranging (LIDAR) is making it easier for archaeologists to explore human settlements in tropical vegetation; previous LIDAR work has found evidence of new cities in Central America, in addition to further enhancing the layout of known settlements such as the Mayan city of Caracol.

For the new study, the researchers used a LIDAR setup emitting up to 200,000 laser pulses each second from a helicopter. Amazingly, the entire operation for the data collection spanned just two days in April 2012 for a total 20 hours of flight time, capturing imagery that would have taken many years to assemble from the ground, if at all. The LIDAR analysis also appears to have discovered what could be an older city beside Angkor Wat.

Angkor Wat

A digital recreation of Angkor Wat temple site (top) based on raw LIDAR digital terrain data (bottom). Image courtesy of PNAS.

The study has revealed new canals, temples and still unidentified manmade features, confirming a metropolitan area that housed many thousands of people, much as the Giza Plateau Mapping Project is doing for cities surrounding the Pyramids construction in Egypt.

As LIDAR technology gets cheaper, it will accelerate our understanding of early human settlements from the lingering geographic footprints we left, traces which can be almost as shallow as a footprint itself. As the authors write in their PNAS paper:

LIDAR technology has recently matured to the point where it has become cost-effective for archaeologists with sufficient accuracy and precision to identify archaeological features of only a few centimeters in size.

Image courtesy of sam garza/Wikimedia Commons

This article originally published at MIT Technology Review
here

Read more: http://mashable.com/2013/06/18/lidar-angkor-wat/

Closest-Ever Images Of Ceres Snapped By Dawn

The peculiaritiesof Ceres’ surface were one of the highlights of 2015, and it looks like the trend is set to continue into 2016. The latest images are the closest pictures of the dwarf planet yet, taken by Dawn as the spacecraft reached its lowest-ever altitude, 385 kilometers (240 miles) above the surface.

“When we set sail for Ceres upon completing our Vesta exploration, we expected to be surprised by what we found on our next stop. Ceres did not disappoint,” Chris Russell, principal investigator for the Dawn mission, said in astatement.

“Everywhere we look in these new low-altitude observations, we see amazing landforms that speak to the unique character of this most amazing world.”

This image from NASA’s Dawn spacecraft shows Kupalo Crater, one of the youngest craters on Ceres. The crater has bright material exposed on its rim and walls, which could be salts. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The image of Kupalo Crater has several interesting characteristics. The crater has bright material on its rim, which could potentially be salts; researchers think that this material is related to the bizarre bright spots located in the Occator Crater. Kupalo is one of the youngest craters on Ceres:it has a diameter of 26 kilometers (16 miles) and its flat floor was most likely formed from the debris and the impact melt. The picture of it has a resolution of 35 meters (120 feet) per pixel.

The fractured floor of Dantu Crater on Ceres is seen in this image from NASA’s Dawn spacecraft. Several bright patches can also be seen.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

“This crater and its recently-formed deposits will be a prime target of study for the team as Dawn continues to explore Ceres in its final mapping phase,” said Paul Schenk, a Dawn science team member at the Lunar and Planetary Institute, Houston.

Dawn also managed to photograph the vast network of cracks on the floor of Dantu Crater, which resemblethe features seen on Tycho Crater on our Moon. The cracking could have formed as the impact cooled or when the crater floor was pushed up after its formation.

Dawn has not only been taking photos but also providing scientists with a heap of data about the dwarf planet’s composition. Dawns gamma ray and neutron detector is studying the abundances of elements on Ceres’surface, and the visible and infrared spectrometer is using a multiwavelength approach to identify the different minerals that form Ceres. The analysis will help astronomers understand how Ceres’ composition evolved.

The spacecraft will remain at its current altitude indefinitely and, while the prime mission is due to end June 30, 2016, further activities will likely be planned after. Dawn is the first mission to visit a dwarf planet and the first mission to orbit two distinct Solar System objects beyond the Earth-Moon system, the other being the large asteroid Vesta.

Photo Gallery

Read more: http://www.iflscience.com/space/new-close-ups-ceres-low-flying-dawn