How to Digitize a 2D Navigation Information in a Seismic Interpretation

The Digitize Navigation (2D only) tool allows you to digitize navigation information for 2D seismic lines directly from images. Images can be imported using different types of formats and georeferenced within the workflow using the GVERSE Geophysics main map view in the seismic interpretation. Once the images are georeferenced, they can be used to digitize shot points for 2D lines which are then exported to a SEG P1 file.

Here’s how you can georeference 2D navigation image and digitize the shot points:

Activate a GeoGraphix project and click on the GVERSE Geophysics icon on the module tool bar to open the application.

Go to File and select an existing interpretation or create a new one.

Go to Tools and click Digitize Navigation (2D only), the digitize navigation info window will open.

Click Browse and search for the image (the supported image types are PNG, JPEG, TIFF and BMP). After finding the image click Open. The image will display on Digitize Navigation window and the image pad will display on the image box.

To georeference the image, two reference points are required for digitization. These points are denoted by maroon and purple colors and are currently at 0,0 pixel position.

To digitize the first point, click Digitize (in the maroon row). Then click on the map where the first digitizing point is going to be. The pixel values will appear next to the maroon box.

Now select the purple row, click Digitize and select the second digitizing point in the map.

After selecting the location for the pixels, the next step is to associate them with the corresponding X and Y location on the map. You can enter the X and Y values manually or click the From Map button to associate the X and Y values with the pixel.

Click on From Map in the maroon row. The Digitize Navigation window minimizes automatically, click on the corresponding location of the first reference point. This information will be used to georeference the image and the location value will appear automatically in the location box.

Repeat the same process for the second pixel and select the correct location on the map.

After georeferencing the image, click Proceed. The Digitize Navigation Info – Step 2 window will appear.

In the Line Name box type the name of the line that you want to use (when digitizing the line, shot points are automatically digitized between two consecutive user provided points. You can specify an increment to control how points are automatically digitized. The Offset value is used in combination with the increment value to assign the final shot point number to each automatically digitized point).

To start digitizing the shot points, click on Digitize SPs (the box will turn blue).

Click on the first shot point on the image, a new window will open where you can enter the shot point number. Click OK.

The first shot point will appear on the list (name, X&Y locations) and the map (If the starting point is 101 and the increment of 10 and offset of 0, the software will automatically assign values of 101, 110, 120, 130 and so on to the digitized points. Regardless of the starting value, multiples of the increment are used to assign subsequent shot point numbers).

Select another shot point on the image (210). In the text box that appears, enter 210 and click OK.

Green boxes are generated automatically between two hard points 110 and 210 in a straight line. These boxes are at a distance of 10 shot points because the increment value was set to 10 (The red entries are user defined – hard points, while the green ones are automatically calculated).

To adjust the position of any digitized point: Select the shot point from the list or click on the image (please ensure Digitize mode is off when selecting a shot point on the image). Hold the <Shift> key and move the shot point to a new location on the image. When finished with all the changes and digitizing, click on Browse and select the location of the new SEG P1 file and click Save.