Recent geoid computations for the Hellenic area

New geoid computations for the Hellenic area are carried out using (a) grav ity anomalies for the land area available from old and new data bases, and gravity data for the sea area derived from altimetry and a recent digitizat ion of sea gravity maps, and (b) a 1 km x 1 km digital terrain model. The E GM96 geopotential model is used as the reference field. In order to assess the quality of the computed geoid heights in the continental area compariso ns were carried out with GPS / leveling heights and the recently available European Gravimetric Geoid EGG97. In the sea area the geoid heights were co mpared with sea surface heights of the recent and more accurate TOPEX/POSEI DON (T/P) altimetry mission. At the end of this article the improvement of the data bases is discussed and same plans for further development in the m ethodological schedule are pointed out. (C) 1999 Elsevier Science Ltd. All rights reserved.