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Airborne Synthetic Aperture Radar and NASA DC-8 Aircraft from 1998
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Kapilapura mound/AIRSAR
This pair of images was crea
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2/12/98
| Date |
2/12/98 |
| Description |
This pair of images was created with data taken by NASA's Airborne Synthetic Aperture Radar (AIRSAR) of the Angkor Wat temple area in Cambodia. The image on the left is a false-color radar image, while the image on the right shows topography data made while AIRSAR was being flown in its interferometric mode. Every tourist to the ancient city visits Angkor Wat but close by, yet unknown, is this Kapilapura mound shown in the upper right corner. The mound was spotted by JPL scientists using the radar data and led archaeologists to survey the area, which is now a deserted forest. The Angkor Wat temple (center of each image) and surrounding moat (large dark rectangle) show up clearly on both images. Forested areas appear yellow on the radar image, cleared areas, including the vegetation-free moat and the area around the temple, appear blue. On the topography image (right), each color cycle, for example from green to green, represents a 20-meter (66-foot) change in elevation. The Kapilapura mound is the bright yellow-purple spot in the upper right. These data show that the Angkor Wat temple is approximately 27 meters (81 feet) high whereas the mound is only 6 meters (19 feet) high. Field checks of the mound area in December 1997 revealed the remains of several temples neglected since cursory French visits in 1904 and 1911 to record inscriptions. The 10th-century inscriptions testify to long term occupation of Angkor. In the same way, villagers occupied the site, which became the city of Angkor before the first temple was built in the 7th century AD. The area shown in both images is 1.25 kilometers by 1.3 kilometers (0.7 miles by 0.8 miles). These data were collected on December 6, 1996 as part of AIRSAR's mission to the Pacific Rim. The AIRSAR instrument flies onboard a NASA DC-8 aircraft. ##### |
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3-D/AIRSAR
This three-dimensional image
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2/12/98
| Date |
2/12/98 |
| Description |
This three-dimensional image was created with data taken by NASA's Airborne Synthetic Aperture Radar (AIRSAR) of the Angkor Wat temple area in Cambodia. Height data generated using radar interferometry, a technique pioneered by JPL that combines two radar images, was used to simulate this perspective view. Every tourist to the ancient city visits Angkor Wat but close by, yet unknown, is this Kapilapura mound shown in the bottom right corner. The mound, a slight but natural rise in the flat terrain, was spotted by JPL scientists using the radar data and led archaeologists to survey the now deserted forest. Temple remains on the mound formed part of the city or 'pura'. Occupational debris undoubtedly increased the height of the mound over time. The Angkor Wat temple is in the center. Its surrounding moat is the wide dark rectangular band. The city moat of Angkor Thom, 'great city', is on the right. In the upper right of the image is the 99 meter- high (325 feet) sacred mountain, Phnom Bakheng. Forested areas appear yellow on the radar image, cleared areas, including the vegetation-free moat and the area around the temple, appear blue. These data show that the Angkor Wat temple is approximately 27 meters (81 feet) high whereas the mound is only 6 meters (19 feet) high. Field checks of the mound area in December 1997 revealed the remains of several temples neglected since cursory French visits in 1904 and 1911 to record inscriptions. The 10th century inscriptions testify to long term occupation of Angkor. In the same way, villagers occupied the site which became the city of Angkor before the first temple was built in the 7th century AD. These data were collected on December 6, 1996 as part of AIRSAR's mission to the Pacific Rim. The AIRSAR instrument flies onboard a NASA DC-8 aircraft. ##### |
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Radar Image with Color as He
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PIA03871
Sol (our sun)
AirSAR
| Title |
Radar Image with Color as Height, Nokor Pheas Trapeng, Cambodia |
| Original Caption Released with Image |
Nokor Pheas Trapeng is the name of the large black rectangular feature in the center-bottom of this image, acquired by NASA's Airborne Synthetic Aperture Radar (AIRSAR). Its Khmer name translates as "Tank of the City of Refuge". The immense tank is a typical structure built by the Khmer for water storage and control, but its size is unusually large. This suggests, as does "city" in its name, that in ancient times this area was far more prosperous than today. A visit to this remote, inaccessible site was made in December 1998. The huge water tank was hardly visible. From the radar data we knew that the tank stretched some 500 meters (1,640 feet) from east to west. However, between all the plants growing on the surface of the water and the trees and other vegetation in the area, the water tank blended with the surrounding topography. Among the vegetation, on the northeast of the tank, were remains of an ancient temple and a spirit shrine. So although far from the temples of Angkor, to the southeast, the ancient water structure is still venerated by the local people. The image covers an area approximately 9.5 by 8.7 kilometers (5.9 by 5.4 miles) with a pixel spacing of 5 meters (16.4 feet). North is at top. Image brightness is from the C-band (5.6 centimeters, or 2.2 inches) wavelength radar backscatter, which is a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color represents 20 meters (65.6 feet) of elevation change, that is, going from blue to red to yellow to green and back to blue again corresponds to 20 meters (65.6 feet) of elevation change. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. In the TOPSAR mode, AIRSAR collects radar interferometry data from two spatially separated antennas (2.6 meters, or 8.5 feet). Information from the two antennas is used to form radar backscatter imagery and to generate highly accurate elevation data. Built, operated and managed by JPL, AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena. |
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