I've recently started investigating NASADEM for some terrain visualisation tasks, and noticed that the total number of tiles on the Earthdata portal is way fewer than the global ASTER GDEM v003 dataset.

NASADEM - 14,520 granules ASTER v003 - 22,912 granules

I've searched extensively but can't find a definitive reason why there's far fewer tiles in the NASADEM dataset. Does anyone know the answer? Both appear to be global coverage and both appear to be 1° x 1° tiles, so I can't really account for the difference in tiles.

It sounds like NASADEM has an improved accuracy, but if there's a lot of missing land data then I'd sooner stick with ASTER for my purposes I think, I just don't want to overlook something obvious.

  • If this is open data then the place to ask your question may be the Open Data Stack Exchange. – PolyGeo Nov 13 '20 at 4:40

Neither NASADEM nor ASTER GDEM has global coverage. NASADEM covers between latitudes 60°N and 56°S, and ASTER GDEM covers between 83°N and 83°S, this significant difference in coverage is probably the main reason that explain the difference in the number of tiles you found.

  • 1
    Thank you so much, that would definitely explain the difference! Appreciate the answer, I couldn't find those differences in degrees covered and that's really helpful to have a succinct answer. I can't upvote you because my reputation is too low but I would if I could! – nmvfx Nov 13 '20 at 18:06

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