Topic:
How to add data to the start of a 2d line.

Description:
Load an additional class of seismic that contains data prior to trace one
of the original class.        

Solution:
An additional class of seismic that contains data prior to the first trace of
the exisiting data cannot be loaded directly through IESX DataManager, but we
can achieve this by using the Seismic > Merge option.

To use the merge option the required class to merge seismic into must exist.
1.) Use Datamanger > Seismic > Copy to create a copy of the existing line in the
    required class.
2.) Load new data to another project.  As usual,when loading a new class, be
    sure that the sp/cdp numbering and increments are the same as the original
    class. It is not essential to load to the same line name/survey and class
    name.
3.) From the original project select DataManager > Seismic > Merge.
4.) Source > Select project, the project to which the new class was loaded.
    Select survey, 2d line and Seismic class.
    Destination > Select survey, 2d line and Seismic class to merge into.
5.) Depending on the extent of the new data, type in the trace offset to
    position the data correctly.  This will probably be a -ve number.
    Select 'Overwriting' to overwrite the original data that was copied.
6.) Merge.
7.) Update Renumber 2d as required.
8.) Note : Additional navigation data is not transferred during seismic merge
           and will need to be loaded seperatly.

The original class should now display with dead traces padded prior to its
original first trace but all interpretation will still post at the correct
position as it is tied to shotpoint number, not trace number.

Example :

Original class   Trace's        1 - 301
                 Shotpoint's 8109 - 8409
                 CDP's       2580 - 2880

Additional class Trace's         1 - 801
                 Shotpoint's  7809 - 8609
                 CDP's        2280 - 3080

Original class is in Project 1, additional class loaded to project 2.
From project 1 select Seismic > Merge and select an offset of -300.




Last Modified on: 04-DEC-98