Gravity anomalies and sea surface heights have been computed on a 0.125¿ gird in the ocean areas from a combined GEOS 3/Seasat altimeter data set. The basic estimation procedure used least squares collocation where model covariance functions are tailored to individual areas through altimeter residual variance scaling. Preliminary tests led to production prediction procedures using a reference model defined by a set of potential coefficients complete to degree 180. Comparisons of the predicted anomalies with ship-derived values showed agreement varying from ¿9 to ¿30 mGal. No correction to the altimeter-implied sea surface heights was made for sea surface topography effects. The maximum anomaly predicted is 396 mGal near Hawaii and the most negative anomaly is -361 mGal over the Puerto Rican Trench. The actual resolution of the predicted quantities was estimated to be about 0.19¿ based on a power spectrum analysis. The resolution is limited by our data selection process which uses 300 data points from a thinned altimeter data set for the prediction of the 0.125¿ in a 3¿¿3¿ block with one data selection and matrix inversion. The predicted data are used to compute 104 potential coefficient spectrums using flat earth approximations developed by Forsberg. The spectra were classified in terms of smooth, mild, or rough areas. The great majority (78) of the spectra were in the smooth classification. Good agreement was found from spectra computed from topographically reduced land data and the mean ocean data, up to degree 800. We found that the spectra decayed as l-3.6 as compared to the decay of l-3 implied by the Kaula model. The gridded data was used to compute 1¿¿1¿ nd 0.5¿¿0.5¿ mean values. The 1¿ mean anomalies were compared to terrestrial data where an rms difference of ¿7 mGal was found in comparing 10,139 values. These new values have allowed us to identify 1¿ mean anomalies (based on terrestrial estimates) that are in substantial error.