SRTM and ASTER tidal refences

yianni

Hi all,

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

thanks all

y

CarrickCon

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

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

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