NODC Code Tables used with Sea Level F184, F185, F186 File formats.

 0505   DECIMATION TECHNIQUE
 ----   --------------------
      1 -- FILTERED
      2 -- SIMPLE AVERAGE - 15 MINUTE VALUES PER GIVEN HOUR; ALL
           HOURLY VALUES PER GIVEN DAY; ALL DAILY VALUES
           PER GIVEN MONTH.
      3 -- SPOT READING
      4 -- OTHER


 0506   DATA REFERENCED
 ----   --------------------
      R -- DATA REFERENCED TO DATUM
      X -- DATA NOT REFERENCED

 0507   INTERPOLATION METHOD
 ----   --------------------
      0 -- NONE
      1 -- SIMPLE
      2 -- CUBIC SPLINE
      9 -- NOT AVAILABLE