The Shuttle Radar Topography Mission (SRTM) generated one of the most-complete high-resolution digital topographic data sets of the world to date. The elevations generated by the on-board C-band sensor represent surface elevations in “bare earth” regions, and the elevations of various scatterers such as leaves and branches in other regions. Elevations generated by a medium-footprint (� 10 m diameter) laser altimeter (lidar) system known as NASA’s Laser Vegetation Imaging Sensor (LVIS) were used to assess the accuracy of SRTM elevations at study sites of variable relief, and landcover. Five study sites in Maine, Massachusetts, Maryland, New Hampshire, and Costa Rica were chosen where coincident LVIS and SRTM data occur. Both ground and canopy top lidar elevations were compared to the SRTM elevations. In “bare earth” regions, the mean vertical offset between the SRTM elevations and LVIS ground elevations varied with study site and was approximately 0.0 m, 0.5 m, 3.0 m, 4.0 m, and 4.5 m at the Maine, Maryland, Massachusetts, New Hampshire, and Costa Rica study sites, respectively. In vegetated regions, the mean vertical offset increased, implying the phase center fell above the ground, and the offset varied by region. The SRTM elevations fell on average approximately 14 m below the LVIS canopy top elevations, except in Costa Rica where they were approximately 8 m below the canopy top. At all five study sites, SRTM elevations increased with increasing vertical extent (i.e., the difference between the LVIS canopy top and ground elevations and analogous to canopy height in vegetated regions). A linear relationship was found sufficient to describe the relationship between the SRTM-LVIS elevation difference and canopy vertical extent.
Validation of SRTM Elevations Over Vegetated and Non-vegetated Terrain Using Medium-Footprint Lidar
M. Hofton,R. Dubayah,J. Blair,D. Rabine
Published 2006 in Photogrammetric Engineering and Remote Sensing
ABSTRACT
PUBLICATION RECORD
- Publication year
2006
- Venue
Photogrammetric Engineering and Remote Sensing
- Publication date
2006-03-01
- Fields of study
Geography, Environmental Science
- Identifiers
- External record
- Source metadata
Semantic Scholar
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- bare earth regions
Terrain areas with little or no vegetation cover, used here to compare radar elevations against exposed-ground lidar elevations.
Aliases: bare-earth regions, bare earth
- canopy top elevations
LVIS-derived elevations representing the upper surface of the vegetation canopy.
Aliases: canopy top, LVIS canopy top elevations
- ground elevations
LVIS-derived surface elevations corresponding to the terrain ground level.
Aliases: ground elevation, LVIS ground elevations
- laser vegetation imaging sensor (lvis)
A medium-footprint airborne lidar system used to provide ground and canopy elevation measurements for validation.
Aliases: LVIS
- linear relationship
A straight-line model used to summarize the dependence between two measured quantities in the analysis.
Aliases: linear model
- shuttle radar topography mission (srtm)
A spaceborne C-band radar mission whose elevation products are evaluated against lidar measurements in this comparison.
Aliases: SRTM
- srtm-lvis elevation difference
The difference between SRTM elevations and LVIS-derived elevations used as the main comparison variable.
Aliases: elevation difference between SRTM and LVIS
- study sites
The five comparison locations in Maine, Massachusetts, Maryland, New Hampshire, and Costa Rica where coincident LVIS and SRTM data were analyzed.
Aliases: sites
- vegetated regions
Terrain areas with vegetation cover, used here to compare radar elevations against lidar-derived canopy elevations.
Aliases: vegetated terrain
- vertical extent
The difference between canopy top and ground elevations, used as a canopy-height-like measure in vegetated regions.
Aliases: canopy vertical extent, vertical range
REFERENCES
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