On the Evaluation of Computer Interpolated Oceanographic Data.
COAST GUARD WASHINGTON D C OCEANOGRAPHIC UNIT
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A Digital Equipment Corporation PDP-5 computer was used by the Coast Guard during International Ice Patrol 1964 for the preparation of oceanographic dynamic topography charts. As programed, the computer interpolated observed data to standard depths using 3-point Lagrange parabolic polynomials above and below the desired depth. This resulted in the visual presentation of 3 possible data values which included the average of the two polynomial points. An oceanographer then decided on the best value to select for dynamical computations at each level while the program was operating. In order to provide a measure of confidence in the average value a rapid point evaluation system was developed. A total allowable error in dynamic height for a station was fixed and proportioned over the standard depths. The average value was automatically chosen when the differences in the polynomial values were within the set error tolerance. Those depths whose values were outside of the tolerance were referred to segments of hand drawn vertical property distribution curves for evaluation. Very reliable data was obtained with a built in estimation of the errors involved.
- Physical and Dynamic Oceanography
- Computer Hardware