Masking by Trace Header

You may specify a field in the trace header that provides information about how the trace is to be used. Two examples are the Trace Identification code (byte-offset 28) and Data use (byte-offset 34). These fields may be useful in masking a portion of the data that should not be included in the output 3D grid or database.

When the SEG-Y file is processed and an Index Database is created, two mask channels are created in the database. The TRACE_MASK channel contains the values from the trace header you specified, or "1" if you elected not to mask using trace headers. The SEGY_MASK channel contains the same values, except where the TRACE_MASK value matches the range you entered.

When an output GDB is created, the sample array channel for traces for which the SEGY_MASK channel is DUMMY ("*") will be represented by an array filled with dummies. For a voxel export, all samples at that trace location will be dummies.

To Use Trace Headers to Mask a 3D Survey

On the Configure tab, select SEG-Y Config.
Click Trace Masking. The Trace Masking dialog appears.
Select Trace Mask.
Specify the Byte offset of the trace header to be compared to the mask value.
From the Data Format drop-down list, select the data type for that field.
In the Dummy these values field, you may specify values that will be masked from your final output. Examples of valid inputs are: [1,3], [1-4], 2, [1-3,5]

Leave the field blank if you want all traces included, but may wish to mask based on these values later.