Permission is hereby granted to journalists to use this material so long as credit is given, and to teachers to use this material in classrooms. This data set has been used at the Naval Oceanographic Office since 1987. World Chart of filtered Geosat sea-surface height data. Contour interval is 0.05 m.
Blue contours are positive, greens are negative.
Notice the difference between seamounts and fracture zones. Once a precise orbit for the satellite is calculated, features in the sea surface become apparent. The rises and depressions in the sea surface are caused by local changes in Earth's gravity field. Except for certain ocean dynamic features, these changes in height of the sea surface correlate well with low-frequency gravity and bathymetry. In 1989 the Naval Oceanographic Office produced its first Geosat product, a worldwide, 5-min, gridded Geosat database gathered from the Geodetic Mission.