SRTM and ASTER tidal refences

yianni
yianni Global Mapper UserTrusted User
in Elevation Data
Hi all,

does anyone know what SRTM and ASTER are referenced to? Lowest / Highest Astronomical Tide or Mean Water Level etc?

thanks all

y

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  • CarrickCon
    CarrickCon
    Answer ✓
    HI Yianni,

    A quick Google search indicates that the vertical datum of ASTER DEM and SRTM is mean sea level and is based on the WGS84 Earth Gravitational Model (EGM 96) geoid. 

    However, be careful as while such data is often adequately accurate in a relative sense, it is not very accurate in a vertical sense (here in Western Australia there is +/- 3 to 4 m difference between both datasets and Australian Height Datum). There are many peer reviewed papers discussing the vertical accuracy of SRTM and ASTER data online.

    Cheers,
    /al
  • CarrickCon
    CarrickCon
    Sorry Yianni I should have said the following above "However, be careful as while such data is often adequately accurate in a relative sense, it is not very accurate in an absolute sense". My bad! 
  • yianni
    yianni Global Mapper User Trusted User
    Hello

    many thanks for this! I have been googling it as well but wasn't getting anywhere so I came here to check with the global mapper crew.

    much appreciated!

    yiannis

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