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Finke River: Remotely Sensed Data
An extensive set of remotely sensed imagery has been acquired and is available for the project. The Australian receiving station acquires every pass of Landsat and SPOT data, most of which is cloud free over this area. A 1972 Landsat MSS image, a 1994 Landsat TM image, two multispectral SPOT images (12/95 and 12/96), and color infrared photography of the Gorge acquired by the Australian government for mapping in the 1970's are available for the study. Several space-based radar scenes from ERS which are suitable for interferometry and radar stereo have already been acquired for the project. The shuttle also acquired SIR-C and X-SAR data over the site in both April and October of 1994. Both AIRSAR and TOPSAR flight lines were obtained by JPL in 1993 over Palm Valley and in 1996 over the Finke River Gorge. A RADARSAT scan mode scene and a JERS scene have been requested over the area.
1996 TOPSAR mosaic of Central Australia
Three DEM's were utilized in the study. A regional 100 m DEM developed by AUSLIG is based on 1:100,000 maps and was initially derived from 20 m contours, streams, and some spot heights. It was iteratively corrected by checking drainage patterns, manually adjusting height, and interpolating via splines. Although no accuracy is specified for this product, it is known to be inadequate for hydrologic applications in low gradient areas [1].
Static GPS surveys were conducted in June 1997 using dual frequency receivers at 28 locations in the 100 km x 100 km study area. An initial interferometric repeat pass DEM was developed using a pair of ERS-1 SAR images acquired during phase A of the ERS-1 mission. A baseline of 120 m was estimated using the GPS measurements at tie points which were visible in the image. The average absolute difference between the interferometric phase and the phase derived from the distance between satellite and GPS receiver locations was 1.443 radians. The resulting 20 m DEM was resampled to 25 m pixel spacing.
TOPSAR data were acquired over the area in September 1993 and November 1996. For this study, the 10 m ground range projected pixel spacing was resampled to 12.5 m as a multiple power of 2 of the other data sets.
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An overview of the study area is shown left where an ERS image and the C band of one of the TOPSAR strips is overlaid on the AUSLIG DEM. |
Last Modified: Wed Apr 14, 1999
CSR/TSGC Team Web
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