Height biases of SRTM DEM related to EGM96: from a global perspective to regional practice

ÜSTÜN A., ABBAK R. A., Ozturk E. Z.

SURVEY REVIEW, vol.50, no.358, pp.26-35, 2018 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 358
  • Publication Date: 2018
  • Doi Number: 10.1080/00396265.2016.1218159
  • Journal Name: SURVEY REVIEW
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.26-35
  • Keywords: Accuracy assessment, Geoid height, Digital elevation model, Earth gravitational model, Shuttle radar topography mission, DIGITAL ELEVATION MODELS, GEOID MODEL, VALIDATION, GPS
  • Kocaeli University Affiliated: Yes

Abstract

It is investigated to what extent EGM96 affects the accuracy of digital elevation model (DEM) produced from the shuttle radar topography mission (SRTM). Global and regional analysis of EGM96 compared with EGM2008 indicate that locally there are large differences distorting to the accuracy level of SRTM DEM. In the absolute sense, the overall geoid differences throughout 1 x 1 arc-degree tiles reach -5m in the northeast and 2-3m in the southern parts of Turkey. A numerical investigation over the test profiles of 200-700 km length running at various directions proves that a possible vertical datum change from EGM96 to EGM2008 yields systematically more accurate height information with an improvement of up to 2.5 m. A GPS-levelling traverse of about 900 km length points out some key patterns of this recovery. Consequently, a correction for the present version of SRTM DEM should be considered in critical implementations of Earth sciences like geoid or water flow modelling, especially for areas where EGM96 shows weak performance.