Angle Gathers

Description Convert offset gathers to the angle domain.
Module(s) Gather Attributes, Explorationist
Requirements Gathers, Velocity Model
Related Mute Gathers, Stacking, Create Gathers
Works with Gathers

  1. Go to the Process tab, click the add (+) button and search for Angle Gathers.
  2. Click Add, provide a name for the Angle Gathers process, and select OK.
  3. Click Close.
  4. Input gather: Select the gather volume to convert.
    • The type of gathers is automatically determined. If offset gathers are selected, the output sequence is set to angle. If angle gathers are selected, the output sequence is set to offset.
  5. Offset: Select the method to determine the offset:
    • Use the OFFSET header: Offset values are provided by the OFFSET header.
    • Calculate offset from SX/SY/GX/GY: Offset values are calculated from the SX, SY, GX, GY headers (which honour the SCALCO header).
  6. Output Sequence:
    • (when using offset gathers) Specify the first angle, last angle and increment of the angle gathers to create.
    • (when using angle gathers) Specify the first offset, last offset and increment of the offset gathers to create.
  7. Angle to offset source: Select either Velocity or Attribute Gathers to calculate the offset-angle relationship.
  8. Velocity volume: The velocity model to use when calculating ray paths through the gathers.
    • Velocity Type and Velocity Units are automatically determined. If required, change to the desired velocity type and unit.
  9. Velocity smoothing length (ms): Optionally apply smoothing to the velocity model before using in calculations.

Note: When exporting angle volumes to SEG-Y, you should be aware that the angle value is stored using centi-degrees at Trace header Byte 139 (Taper Type, tatyp). Centi-degrees are degrees * 100 and are used by Insight to preserve 2 decimal places of accuracy.