Established in 2020, DEMIX (DEM Intercomparison eXercise) is a CEOS / WGCV / TMSG initiative. The objective of DEMIX is to compare global DEMs, and in particular, those at 1” arcsecond such as SRTM, ASTER GDEM, ALOS World-3D, NASADEM, COP-DEM, and FABDEM to allow different users to select the one that best suits their needs in their areas of interest. This choice is based on the results of criteria tested in different areas where both quantitative and qualitative results can be freely combined for the candidate DEMs. The DEMIX project, developed out of a JRC workshop on Global DEM Benchmarking in 2019, started in July 2020 and is rolled out in three subgroups:

• Subgroup 1 – Terminology and Analytical Basis,
• Subgroup 2 – Algorithms and Software
• Subgroup 3 – Platforms and Processing

For a brief overview of the project please refer to the ISPRS2021 conference paper or watch this 10 minute introductory video.

The TMSG Digital Elevation Model Intercomparison eXercise (DEMIX) team set up jointly with the International Society of Geomorphometry (ISG) has completed and published its final report following six years of work.

The team assessed a range of widely used global DEMs using reference data covering different terrain and land-cover types. The exercise developed a consistent, statistically sound approach for comparing DEM products and evaluating their performance across different conditions. The work provides users with evidence to help identify the most suitable DEM for different applications, terrains and geographic areas, rather than assuming that a single DEM is appropriate for all uses. It also provides recommendations for DEM providers and practical resources, including open-source tools, to support future comparisons. The final results and resources are available to the wider community. The report has also been promoted through a CEOS article and social media.