The SEG-Y defined binary header values (Barry, et al., 1975). The
SEG=Y files on this CD-ROM conform to this standard.

Byte Numbers   Header Value Description
3201 - 3204    Job identification number.
3205 - 3208    Line number.
3209 - 3212    Reel number.
3213 - 3214    Number of data traces per record.
3215 - 3216    Number of auxiliary traces per record.
3217 - 3218    Sample interval, microseconds, this file (reel).
3219 - 3220    Sample interval, microseconds, original field
               recording.
3221 - 3222    Number of samples per data trace, this file
               (reel).
3223 - 3224    Number of samples per data trace, original field
               recording.
3225 - 3226    Data sample format code: 1 = floating point (4
               bytes)
                                        2 = fixed point (4 bytes)
                                        3 = fixed point (2 bytes)
                                        4 = fixed point with gain
                                            code (4 bytes).
3227 - 3228    CDP fold.
3229 - 3230    Trace sorting code:      1 = as recorded (no)
               sorting)
                                        2 = CDP ensemble
                                        3 = single fold
               continuous profile
                                        4 = horizontally stacked
3231 - 3232    Vertical sum code:       1 = no sum
                                        2 = two sum
                                        ...
                                        N = N sum (N = 32,767)
3233 - 3234    Sweep frequency at start.
3235 - 3236    Sweep frequency at end.
3237 - 3238    Sweep length, ms.
3239 - 3240    Sweep type code:         1 = linear
                                        2 = parabolic
                                        3 = exponential
                                        4 = other
3241 - 3242    Trace number of sweep channel.
3243 - 3244    Sweep trace taper length, ms, at start if tapered.
3245 - 3246    Sweep trace taper length, ms, at end.
3247 - 3248    Taper type:              1 = linear
                                        2 = cos
                                        3 = other
3249 - 3250    Correlated data traces:  1 = no
                                        2 = yes
3251 - 3252    Binary gain recovered:   1 = yes
                                        2 = no
3253 - 3254    Amplitude recovery method:    1 = none
                                        2 = spherical divergence
                                        3 = AGC
                                        4 = other
3255 - 3256    Measurement system:      1 = meters
                                        2 = feet
3257 - 3258    Impulse signal:          1 = Upward = negative
               number.
                                        2 = Upward = positive
               number.
3259 - 3260    Vibratory polarity code - seismic signal lags
               pilot signal by:
                                        1 = 337.5 -    22.5
               degrees
                                        2 = 22.5  -    67.5
               degrees
                                        3 = 67.5  -    112.5
               degrees
                                        4 = 112.5 -    157.5
               degrees
                                        5 = 157.5 -    202.5
               degrees
                                        6 = 202.5 -    247.5
               degrees