I have read a few things from the ASF website with a view to finding out the vertical accuracy of the ASF 12.5m by 12.5m DEM, but am yet to be fortunate. I was wondering if anybody knows and is willing to share?
Hi Elijah!
We compared the ASF product (RTC-12.5 m) with the SRTM. The paper is in portuguese, but you can take a look in the figures.
https://www.researchgate.net/publication/323476923_PRODUTOS_SRTM_E_RTC_NA_CARACTERIZACAO_MORFOMETRICA_E_TOPOGRAFICA_UMA_ABORDAGEM_COMPARATIVA
Hope It helps
The 12.5m DEM originates from the National Elevation Dataset (NED13, see source [1]). Various accuracy measures are given in the report of source [2]. It was assessed using 25,000 reference points throughout North America. Some statistics on the absolute vertical accuracy:
Min: - 24.64
Max: 15.57
Mean: -0.29
StD: 1.52
RMSE: 1.55
[1] https://media.asf.alaska.edu/uploads/RTC/rtc_product_guide_gamma_1.1.pdf
[2] https://pubs.usgs.gov/of/2014/1008/pdf/ofr2014-1008.pdf
- The DEMs were pre-processed by ASF to a consistent raster format (GeoTIFF) from the original source formats: height (*.hgt), ESRI ArcGrid (*.adf), etc. Many of the NASA-provided DEMs were provided as orthometric heights with EGM96 vertical datum. These were converted by ASF to ellipsoid heights using the ASF MapReady tool named geoid_adjust. The pixel reference varied from the center (pixel as point) to a corner (pixel as area). The GAMMA software, used to generate the terrain-corrected products, uses pixel as area and adjusts DEM coordinates as needed. Where more than one DEM is available, the best-resolution DEM is used for processing. Complete DEM coverage from a single DEM source is required for processing to proceed.
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