[Proj] geoid in Kalimantan, Indonesia

[Frans Buschman]

Hello,

In a coastal region in East Kalimantan, Indonesia, we measured with a GPS promark3 system height differences of several water level gauges with respect to the WGS-84 ellipsoide and datum. The stations are about 30 km apart and we think that the precision of the measurements is within 10 cm. 

>From the water level gauges we want to see in what direction water should be flowing, so we want the want to derive the height differences with respect to a geoid. For Kalimantan no detailed geoid seems to exist, so I would like to convert measured height differences on the WGS-84 ellipsoide to height differences on a global geoid. Which geoid is best for this purpose and how can I make the conversion? Could you give an estimate of the error you make with this conversion?

Thanks!
Frans

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Frans Buschman (PhD student)
Department of Physical Geography
Institute for Marine and Atmospheric Research Utrecht
Utrecht University
P.O. box 80.115 / Heidelberglaan 2
3508 TC Utrecht, the Netherlands
Room 211 in Jan Zonneveldvleugel
Phone: +31 - (0)30 2532778
Fax: +31 - (0)30 2531145
mail: f.buschman at geo.uu.nl
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