Setting column parameters: The Column Menu

Exporting a config file

This option will export the current column configuration to the standard config file format. The configuration can be exported to the default config file "SegyTracker_Config.cfg" or to a new file that could be used for specialized types of SEGY files. The current column configuration is exported so if you have changed the column order, column names, column format, or byte location these changes will be reflected in the new config file.
In addition to column configuration the config file also contains default settings such as trace display and map display parameters and default directories. These values will be used as initial defaults for various dialog boxes.
Use the tabs on the Export Column Defaults dialog to define the config file
Segy Table Columns: This dialog shows the current column configuration. If you wish to add more columns to the config file you must add them before exporting the new configuration. Use the Add user editable column or Populate new or existing columns functions to add new columns.
To omit columns from the config file uncheck the column name check box. You can also change the column data format and byte locations as well as the number of decimal places to display in floating point values.
Header Values: This dialog sets the default format and byte location for SEGY fields such as shotpoint, CDP, X and Y values. These values are not used for setting column parameters but instead are used as starting default values for other dialogs like those for map display and trace display parameters.
Values entered here can always be changed by the user at run-time.
Trace Display: These are the default trace display settings for traces per inch, inches per second plot direction, etc.
Map Display: Settings for map display annotation.
Format Codes: Set the export format code used for SEGY export. See the dialog for the discrepancy between CSEG (Canadian) and SEG (U.S.) format codes for IEEE float and single byte data.
Note that these values are not used by SegyTracker at present but will be used for export functions that may be added later.
Graph Display: Set default direction for graph display. Not used at present.
Directories: Sets the default directories for SegyTracker to use in file browsers. Set the license directory, the starting directory for searching for SEGY files, directories for survey export and config file export. Note the default config file directory is always the user's home directory. The one described in this dialog would be used for non-stndard config files.

Importing a config file

Selecting this function will pop up a file browser for selecting a non-standard config file, or to reload the standard config file from the user's home directory.
Note that a new configuration must be imported or defined before importing SEGY files and will apply only to the table created by that import. Existing tables are not affected by a new configuration.

Add a user editable column

This function will add a new, blank, editable text column to the currently selected table.
Enter a name for the new column, blanks are OK, special characters are not. The new column will be inserted to the right of the column you select from the drop-down list.
Once added to the table text data can be entered in the column either by manually typing in each cell or pasting from the clipboard. You can use the copy and paste functions from the edit menu to copy values from other table columns.

Populate new or existing columns

These functions will add new columns to the existing table or refresh existing columns with new data.

Populate with pre-defined data

This option will add one or more columns populated with pre-defined data. That is data that is read from the SEGY file with a set format and byte location.
An example would be the format code which is always found in bytes 25-26 of the binary header. The other type of pre-defined data is derived from the SEGY file using one or more attributes or fields from the file. As an example the number of traces in the file.
The new columns will be inserted to the right of the column selected from the drop-down list.
There are 3 tabs on this dialog that define different types of columns.

Standard

Use this tab to set the standard predefined columns. The available columns are:
File Name: Derived from the SEGY file path.
Traces: Number of traces in the SEGY.
Size MB: File size in megabytes.
Rec Len: Record length in milliseconds.
SRate: Sample rate in milliseconds.
SFmt: Sample format such as IEEE(1) with the number in brackets being the value read from the binary header.
HighByte: True if SEGY is in high byte order.
Rd Only: True if file is read only.
Linked To: If SEGY path is a Unix link the value in the column is the path to the target file.

Amplitudes

These columns will display the peak, average, or RMS (root, mean, square) amplitude for each selected SEGY in the current table.
Only live sample values are considered for these values. Note that due to the file I/O involved these options can be slow on very large files.
The peak amplitude option can be calculated for all samples in all traces which is the usual case. The peak amplitudes for a percentage of all amplitudes can also be calculated. The defaults are to calculate the peak for 100 percent of all samples, 99.995 percent of all samples, that is discarding the largest .005 percent of amplitudes, or 99.5 percent of all samples. The maximum amplitude to be considered can also be set to disregard spikes in the sample values.
The average amplitude is the average of the average sample value for all the traces of the SEGY.
The RMS amplitude is the average of the RMS value for each trace. To compute the RMS value each sample value in the trace is squared. The RMS is the square root of the mean of the squared samples.

SeisX / SeisWare

These columns will display data encoded in SeisX / SeisWare SEGY files
The available columns are:
SeisX / SeisWare Version: Displays the SeisX version used to create the SEGY file. The only significant difference between versions is that versions one to three used a format code "1" to denote IEEE float and "6" to denote IBM float. This was a direct opposite to the CSEG standard. Versions four and later use the standard CSEG value of a "1" for IBM and a "6" for IEEE. The geometry of the file, 2D or 3D is also displayed so that the cell value could look like "2D_4.xx" for a version four 2D file.
SeisX / SeisWare Lname: Displays the line name / 3D volume name written in bytes 301 - 320 of the binary header
SeisX / SeisWare Desc: Displays the description text encoded in bytes 3120 to 3179 of the EBCDIC header
EPSG Code: Displays the EPSG code in bytes 161-164 of the binary header as described in the SEGY standard used by Devon and others.

Populate new column(s) with data from trace headers

These columns will be populated with data from the trace headers.
The data from the first trace can be displayed in a single column. Alternatively the data from the first and last trace or the minimum and maximum values from all the traces in the file can be displayed in two columns. The column(s) will be inserted to the right of the column selected in the drop-down list.
Only the SEGYs in selected rows will be populated. The other rows will be left blank.
There are six preset names for the columns although the column names can be changed later. The preset column names are:
Shotpoint: Column name SP. If two columns created they would be called First SP and Last SP or Min SP or Max SP.
CDP: Column names CDP or First CDP and Last CDP or Min CDP and Max CDP.
X Coordinate: Column names X or First X and Last X or Min X and Max X.
Y Coordinate: Column names Y or First Y and Last Y or Min Y and Max Y.
3D Inline: Sometimes called 3D line number. Column names Inline or First Inline and Last Inline or Min Inline and Max Inline.
3D Xline Sometimes called 3D trace number. Column names Xline or First Xline and Last Xline or Min Xline and Max Xline.
User defined columns can be created with a name of your choosing. Blanks are OK, special characters are not. User defined names cannot start with "First", "Last", "Min", or "Max". User column names of "SP", "CDP", "X", "Y", "Inline", or "Xline" are OK so long as those columns do not already exist
For all columns you set the start byte position and format. For floating point values you can also set the number of decimal points to display.
If you try to add a column name that already exists you will be warned and the column wil not be added.
This dialog will stay up after the "Add Columns" button is clicked so you can add multiple columns in one operation

Alter parameters for existing columns

Use this dialog to re-populate all or some of the rows of any column.
The data displayed in a column need not be all read from the same byte location or format. For instance the shotpoint column could contain data read from bytes 17-20 in 32 bit integer format and some read from bytes 189-193 in IEEE floating point.
Of course when importing SEGYs into a table all rows will be populated from one byte location and one format. This dialog allows you to select any rows which need to be re-populated and set the new read parameters while leaving the data in the unselected rows untouched.
All the columns in the current table wil be listed in the dialog. Select the ones to be re-populated by clicking on the checkbox next to the column name

Populate with data from binary header

This function will create columns filled with data from the binary header.
Enter the start byte position and the format of the data to be read.
This function can either populate a new column or an existing one. Only the SEGYs in selected rows will be re-populated
The column will be inserted to the right of the column selected from the drop-down list.

Populate with text string from binary or EBCDIC header

This function will create columns populated with ASCII text data read from the EBCDIC or binary headers of the SEGYs in selected rows.
Select the header to read the text from and the format. Note that the format is the format of the data in the header. Regardless of whether EBCDIC or ASCII is choosen the data in the table will be in ASCII.
Define the start and end byte to read the text from starting from the first byte in the selected header
The text can populate a new or existing column and will only populate the rows that are selected.
The column will be inserted to the right of the column selected from the drop-down list.