Convert ASCII to seismic

Convert ASCII to seismic builds 2D lines and 3D volumes from a plain ASCII text file of scattered X / Y / Z / Value points (.txt). Unlike a raw trace load, this is an interpolation and gridding operation: the point values are resampled along Z and gridded into traces, and the result is stored internally as SEG-Y.

Purpose

Turn an unstructured table of point measurements into regular seismic traces. Each unique X / Y position becomes a trace, the Z column supplies the sample position (time or depth) and the Value column supplies the amplitude. Points are interpolated vertically to a fixed sample rate; for a volume the traces are then gridded into a full cube. The output is amplitude data, not geometry-only, and can be treated as any other seismic object afterwards.

Launching the import

The tool is reached from the Data manager context menu on the seismic data node. Two entries are available:

Convert ASCII data to line — produces one or more 2D lines.
Convert ASCII data to volume — produces a 3D volume (pseudo-cube).

Either entry first opens a Load ASCII data file dialog where one or more text files are selected, then the Import ASCII data column-mapping wizard.

[image: placeholder_Data_manager_seismic_node_right-click_me.png]

Step-by-step

Right-click the seismic data node in the Data manager and choose Convert ASCII data to line or Convert ASCII data to volume.
In the Load ASCII data dialog, select one or more .txt files.
In the Import ASCII data wizard, set the column separator and the first / last data rows, then map the file columns to the Survey ID (optional), X, Y, Z and Value fields.
Set the vertical and interpolation options (domain, sample rate, interpolation method); for a volume also set the bin step and gridding options described below.
Confirm the wizard. Points sharing a Survey ID are converted together, so a single file with several IDs yields several lines.

[image: placeholder_Import_ASCII_data_wizard_showing_column_.png]

Parameters

Column mapping:

Survey ID — optional. When present, its value groups points into separate lines / surveys.
X, Y — required. Trace position in the survey coordinate system.
Z — required. Vertical sample position (time or depth).
Value — required. Amplitude written into the trace.

Vertical / interpolation options (both lines and volumes):

Data is 2D — chooses line versus volume output. It is preset by the menu entry used and is only editable when launched without a fixed choice.
Data is in time domain — marks the output as time (otherwise depth).
Invert Z axis — negates the Z column, for files where Z increases upward.
Output sample rate — vertical sampling interval of the created traces.
Interpolation method — how values are interpolated between points along a trace: Linear or Spline.

Volume gridding options (used only for Convert ASCII data to volume):

Step X, Step Y — bin grid cell size used to build the output cube.
Kriging covariance — covariance model used when filling empty bins: Spherical, Gaussian or Exponential.
Kriging search radius — distance around each bin within which input traces are collected.
Kriging min number of points — minimum neighbour count; if the radius yields fewer, the nearest points are used instead.

The converted data is held internally in the g-Space SEG-Y representation, so once imported it behaves like any other seismic line or volume.