4.5.5 Reference Shift

The Reference shift attribute moves the extraction position in 3D space.

Description: The Input attribute is extracted at the shifted position. Original reference (extraction) point has inline crossline coordinates (0,0). Relative number 1 means the next inline or crossline, respectively. The vertical shift is specified in ms using the Time option, or can be derived using Steering.

Steering is specified in one of the following ways:

• None: The reference position is not shifted vertically.
• Central: The reference position is vertically shifted according to the dip and azimuth information at (0,0,0) from the SteeringCube.
• Full: The reference position is vertically shifted according to the dip and azimuth from the SteeringCube, from trace to trace from the starting position (0,0,0) to the position specified at Inl/Crl shift.
• Constant direction: The reference position is vertically shifted according to a user defined Apparent dip and Azimuth.

Shifting the reference position is a form of directivity that is useful in multi-attribute analysis. For example, to highlight flat spots, one may consider training a neural network on attributes extracted in three horizontally aligned windows.