The Trace Data Panel is a powerful and versatile tool for accessing and editing trace header information. This window provides comprehensive details about all trace headers, including their format type, starting byte location, values, ranges, histograms, and an expression column for modifying trace header values.
Key Features of the Trace Data Panel
1.Field Column
Displays the name of the trace header, such as FFID, CHANNEL, CDP, etc.
2.Item Type Column
Indicates the data type of each trace header (e.g., Int4 for 4-byte integers or Int2 for 2-byte integers). Knowing the format is essential for accurate data manipulation.
3.Start Byte Column
Shows the starting byte location of the trace header in the SEG-Y file. This information is critical for mapping header values to their physical location in the file.
4.Value Column
Displays the current value of the selected trace header. For example, the value of the OFFSET trace header might be 3172.968000, indicating the distance between the source and receiver in meters.
5.Ranges Column
Provides the minimum and maximum values for each trace header across the dataset. For instance, the FFID (field file identifier) range might be [60.000; 999.000]. This helps users quickly identify variability or anomalies in their data.
6.Histogram Column
Visualizes the distribution of trace header values across the dataset. This column is particularly helpful for spotting patterns, trends, or outliers in your data. For example, a histogram for the OFFSET field might reveal a bell-shaped distribution, indicating a uniform spread of offset values.
7.Expression Column
Allows users to input custom expressions to modify trace header values. For example, to convert coordinates from meters to feet for Source_X and Source_Y, users can enter the following expression:
Int4(73) * 3.28084
oInt4: Specifies the data type of the trace header.
o73: Denotes the starting byte location of the trace header.
o*: Represents the multiplication operator.
o 3.28084: Conversion factor from meters to feet.
Modifying Trace Header Values
1.Enter Expressions
Input the desired formula in the Expression column for the target trace header(s). For example, to multiply all offset values by 1.5, you can input Int4(37) * 1.5.
2. Apply Changes
After entering the expressions, click on Read Headers to update the trace header values in the panel.
After modifying trace headers using the Trace Data Panel, you can apply the changes to the current SEG-Y file by following these steps:
1.Navigate to the Tools Menu
Go to the Tools menu and select Save Trace Header.
2.Select Headers to Modify
In the dialog that appears, choose the specific trace headers you want to apply changes to. This ensures that only the selected headers are updated in the current SEG-Y file.
3.Apply Changes
Once the desired headers are selected, click Apply. This action will update the current SEG-Y file with the modified trace header values.
To save the modified trace headers as a new SEG-Y file:
1.Navigate to the Tools Menu
Go to the Tools menu and select Save Seg-Y
2.A pop-up window will appear, allowing you to:
oSave all traces or only selected traces.
oResample the data if required.
3.Choose the appropriate options and click OK.
4. In the next pop-up window, specify the file name with the .sgy or .segy extension and click Save.
If there are issues with the expressions or incompatible data formats, the system will notify the user. Ensure all formulas match the trace header's data type for successful updates.