There are a few different methods for digitizing seismic lines in Didger.

Method 1
The simplest method of digitizing seismic lines involves digitizing the travel time (or depth) for the desired horizons at the shot point locations. This method requires you know the real world XY locations of each shot point location.

1. Use the File | Import command to import the image into Didger.
2. Calibrate the image during the import process in the Image Registration and Warping dialog window. Use the Shot Point number as the Reference X coordinates and the Time (or Depth) as the Reference Y coordinates. Or put the seismic lines on a digitizing tablet and calibrate the tablet using the parameters described above. 
3. Digitize each intersection of a horizon with a shot point line by drawing symbols with the Draw | Symbol command. 
4. Once all the intersections are digitized, export the data to a DAT file by clicking File | Export and changing the Save as type to DAT Golden Software Data (*.dat). 
5. Open the DAT file in a spreadsheet program (like Surfer or Excel) and enter the known world XY locations into two new columns for each Shot Point (X value). 

Now you have the Shot Point number, the time/depth variable, and the X and Y coordinates for all shot points where they intersect horizons.

Method 2
If you desire greater density of data than than Method 1 offers (for example, if you want data in between the shot point locations), you can digitize a section based in Northing, Easting, and Time.

1. Use the File | Import command to import the image into Didger.
2. Calibrate the image using Time as the Reference Y coordinates and whichever geographic value (i.e. Northing) changes most along the line as the Reference X coordinates. Use shot point locations as the calibration points. 
3. Digitize along each horizon line as a polyline, and at each shot point location as a symbol, and manually entered the Easting value as the Primary ID. 
4. Once all everything is digitized, export the data to a DAT file by clicking File | Export and changing the Save as type to DAT Golden Software Data (*.dat). This gives Northing, Time, and Easting values for each shot point location, and Northing and Time values for the horizons in between. 
5. Opened the DAT file in a spreadsheet program (like Surfer or Excel) and interpolate Easting values between shot points using a linear formula.

Updated August 16, 2018