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| Titel |
Mapping from Formosat-2 stereo images: digital elevation model validation and accuracy assessment |
| VerfasserIn |
Po-Li Chen, Cheng-Chien Liu |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026803
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| Zusammenfassung |
| Digital Elevation Model (DEM) generated from satellite stereo image data has been widely
used in change detection of elevation, such as tracking the glacier movement, estimating the
landslide volume, and mapping the surface topography. As the spatial resolution of
satellite stereo image data is increasing, the generated DEM is expected to reveal
more and more details of the topography. In addition, since the applications of
rapid response are increasing, the time required to collect the satellite stereo image
data is expected to get shortened as well. The successful operation of Formosat-2,
launched on 21 May 2004, has enabled the collection of both high-spatial- (2 m) and
high-temporal-resolution (daily) images. Together with its capability of pointing ±45 degrees
to both along and across track directions, Formosat-2 is able to take stereo images for
any scene in its coverage area. This provides an ideal source of stereo image data
for rapidly generating a regional DEM to respond to the urgent needs in a timely
manner.
This research describes the procedure of generating a DEM from Formosat-2 stereo
image data. The mountainous region of the catchment of Tseng-Wen Reservoir (TWR) is
selected as the study area, where the orthorectified aerial photos (50 cm) and their derived
DEMs (5 m) are available. A total of 120 ground control points (GCPs) are uniformly
collected from one aerial photo and identified on the corresponded Formosat-2 stereo images,
with the intention to build the rational polynomial coefficients (RPCs) of Formosat-2 orbit.
A series of sensitivity tests are performed to examine how the generated DEM is
influenced by various factors, including RPCs, tie points and GCPs. The accuracy of the
generated DEM is assessed and validated against the aerial DEM, ASTER DEM, and
SRTM DEM. The results demonstrate that Formosat-2 stereo image data is ideal for
rapidly generating a regional DEM to respond to the urgent needs in a timely manner. |
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