FIGURES 



Page 

 1 . The R.. Grid of Data Values for Input into the Bicubic Spline Algorithm . 1 1 



2. The Function g(x,y) 16 



3. Geometry for Computing the Gravitational Potential Due to a 



Point Mass 18 



4. Contour Chart of the Gravity Anomalies Generated by 16 Point Masses 

 with Contour Interval of 5 mgls 20 



5. The Two-Dimensional Fourier Transform of the Entire 80 x 80 Minute 

 Model Field with One Data Interval Equal to One Minute and 



Contours in Normalized Units 22 



6. Model 1 - Simulated Survey Tracks Based on the Fourier Transform 

 of the 80 x 80 Minute Model Field. Nominal Track Spacing and 

 Sampling Interval Equal to 3 nm 23 



7. Contour Chart of Model-1 Point-Value Residuals (Spline Interpolation 



vs. True Value) with a Contour Interval of 0.5 mgl 25 



8. Histogram for Model-1 Spline Point-Value Residuals 26 



9. Contours of the 12° Least-Squares Polynomial Surface Generated 



from Model-1 Data. Contour Interval is 5 mgls 27 



10. Histogram for Model 2 Spline Point-Value Residuals 29 



1 1 . The Two-Dimensional Fourier Transform of the Model Field from 

 Longitude 0' to 60' and Latitude 10' to 70' with One-Data Interval 



Equal to One Minute and Contours in Normalized Units 30 



12. Simulated Survey Tracks Based on the Fourier Transform of the 60 x 60 

 Minute Model Field. Nominal Track Spacing and Sampling Interval 



Equal to 2 nm 31 



13. Contour of Model-3 Point-Value Residuals (Spline Interpolation vs. 



True Value) with a Contour Interval of 0.5 mgl 32 



