Abstract
This paper provides some recommendations concerning the use of version 4.1 of the near-global 3 arcsec Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) distributed by the Consortium for Spatial Information (CGIAR-CSI). This product is considered by most users to be a void-filled version of the finished grade NASA SRTM DEM. However, in non-void areas, these DEMs can exhibit relative geolocation shifts and spatially correlated elevation differences up to tens of meters, the location and extent of which depends on the geographical location and on the download mirror of the version 4.1 product. Such differences are found to be partly due to changes introduced by NASA SRTM version 2.1, with respect to NASA SRTM version 2.0, on which CGIAR-CSI version 4.1 is based, and partly to processing and/or annotation errors affecting the CGIAR-CSI version 4.1 DEMs.
Highlights
For over a decade, the near-global Digital Elevation Model (DEM) derived from the ShuttleRadar Topography Mission (SRTM) [1] has been exploited for a broad range of applications, including, hydrology, geomorphology, volcanology, seismology, glaciology and forest ecology [2,3]
This study itself stems from an application, namely Differential Synthetic Aperture Radar Interferometry (DInSAR), in which a DEM is used to separate the contribution of topography from that of surface deformation due to a variety of geophysical phenomena [4]
This paper describes a global inter-comparison of Shuttle Radar Topography Mission (SRTM) DEM versions 4.1 (CGIAR-CSI) and
Summary
The near-global Digital Elevation Model (DEM) derived from the ShuttleRadar Topography Mission (SRTM) [1] has been exploited for a broad range of applications, including, hydrology, geomorphology, volcanology, seismology, glaciology and forest ecology [2,3]. Versions 4.1 and 2.1 are among the few near-global DEMs, which can be accessed through an FTP or HTTP URL, without interacting with a graphical selection/download API, and without any restriction on the number of tiles, which can be downloaded. These features simplify data access, in particular for large-scale data analysis, and allow applications to create DEMs by automatically downloading and subsequently cutting/merging the relevant SRTM tiles
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