| Format | Byte | Key | Encana (Note Key 1=Must Have 2=Should Have) |
|---|---|---|---|
| A8 | 1 | 1 | Reference Number (Line id), leave bytes 9-12 for check programs |
| Be sure to pad field ascii nulls and not underscores (ascii octal 137) | |||
| I2 | 13 | # data traces/record | |
| I2 | 15 | # auxiliary traces/ensemble | |
| I2 | 17 | 1 | sample interval |
| I2 | 19 | sample interval original field | |
| I2 | 21 | 1 | Number of data samples per trace or maximum number of samples |
| per trace. | |||
| I2 | 23 | samples /data trace original field | |
| I2 | 25 | 1 | Data sample format code: |
| 1 = IBM floating point (4 bytes), use with SeisX flag = 91 | |||
| 2 = IBM full word integer (4 bytes) | |||
| 3 = IBM half word integer (2 bytes) | |||
| 4 = fixed point with gain code (4 bytes) | |||
| 5 = IEEE floating-point (4 bytes) | |||
| 6 = SUN IEEE Big Endian (Canadian) Use with SeisX flag = 92 | |||
| 8 = 1-byte two's complement | |||
| I2 | 27 | CDP (CMP) Fold nominal for line | |
| I2 | 29 | Trace sorting code: 4 = stacked, 2 = cdp, 1 = as recorded(shots) | |
| I2 | 31 | Vertical sum code | |
| I2 | 33 | Sweep frequency start | |
| I2 | 35 | Sweep frequency end | |
| I2 | 37 | Sweep length | |
| I2 | 39 | Sweep type code 1=linearà | |
| I2 | 41 | Trace number of sweep channel | |
| I2 | 43 | Sweep trace taper length at start | |
| I2 | 45 | Sweep trace taper length at end | |
| I2 | 47 | Taper type | |
| I2 | 49 | Correlated data traces | |
| I2 | 51 | Binary gain recovered 1=yes 2=no | |
| I2 | 53 | Amplitude recovery method | |
| I2 | 55 | measurement system | |
| 0 = unknown | |||
| 1 = meters | |||
| 2 = feet | |||
| I2 | 57 | Impulse signal polarity | |
| I2 | 59 | Vibratory polarity code | |
| I4 | 61 | Number of traces in file | |
| -3 | 65 | Mean absolute value of all samples in all the traces in the file | |
| I2 | 69 | Domain code: 0=time 1=amplitude 3=phase 4=depth | |
| A6 | 71 | Survey Datum, eg NAD27, WGS84 | |
| A6 | 77 | Survey Grid, eg ATS2.6 | |
| I2 | 83 | Station interval | |
| A12 | 85 | Unused | |
| I4 | 97 | The time of the first sample in ms. May be negative zero or positive. | |
| -3 | 101 | START_WINDOW = 0 | |
| start of window over which peak average & RMS are calculated | |||
| -3 | 105 | END_WINDOW (end of trace) | |
| end of window over which peak average & RMS are calculated | |||
| -3 | 109 | PEAK_VAL | |
| -3 | 113 | AVG_VAL | |
| -3 | 117 | RMS_VAL | |
| I4 | 121 | TRACE_SORT = 0 | |
| -3 | 125 | 2 | SEIS_DATUM elevation |
| -3 | 129 | 2 | SEIS_REPLACEMENT_VELOCITY |
| I4 | 133 | MAXIMUM_ENSEMBLE_NUMBER = 0 (stack) (max traces/gather) | |
| A4 | 137 | Unused | |
| -3 | 141 | latitude minimum | |
| -3 | 145 | longitude minimum | |
| -3 | 149 | latidude maximum | |
| -3 | 153 | longitude maximum | |
| I4 | 157 | central meridian | |
| I4 | 161 | UTM zone | |
| A4 | 165 | Unused | |
| -3 | 169 | NE corner UTM X | |
| -3 | 173 | NE corner UTM Y | |
| -3 | 177 | NW corner UTM X | |
| -3 | 181 | NW corner UTM Y | |
| -3 | 185 | SE corner UTM X | |
| -3 | 189 | SE corner UTM Y | |
| -3 | 193 | SW corner UTM X | |
| -3 | 197 | SW corner UTM Y | |
| I4 | 201 | 3D xline START_X | |
| I4 | 205 | 3D inline START Y | |
| I4 | 209 | 3D time START_Z | |
| I4 | 213 | 3D xline END_X | |
| I4 | 217 | 3D inline END_Y | |
| I4 | 221 | 3D time END_Z | |
| I4 | 225 | AXIS_TRACE = 1 | |
| I4 | 229 | AXIS_LINE = 2 | |
| I4 | 233 | AXIS_TIME = 3 | |
| A20 | 301 | 1 | LINE_NAME pad field with nulls ascii 0 and not underscore |
| -3 | 341 | TOTAL_PHASE rotation applied | |
| -3 | 345 | TOTAL_GAIN | |
| -3 | 349 | TOTAL_GAIN_EXP | |
| I4 | 353 | ROTATION orientation of 3D (number 0 to 7) | |
| I4 | 357 | CT_1 = 0 | |
| I4 | 361 | CT_2 = NumXline -1 | |
| I4 | 365 | CT_3 = NumLines * NumXlines -1 | |
| I4 | 393 | GEOMETRY | |
| 2= 2D line 3=3D line | |||
| Byte | 399 | 2 | SeisX 3.5,6 = 91 SeisX 4.0 = 92 otherwise = 0 |
| Byte | 400 | 2 | Encana = 100 otherwise 0 |