Content Comparison

The auto tracker can be very useful on strong reflectors. However when interpreting the base of sediments, the manual approach is probably better.

1. Use a combination of the editing methods above to do an interpretation of the seabed

2. Before starting on the base of sediments, we need to tell the interpreter that we are starting on a new horizon.

    

3. Click Browse on the IHorizon row, and select Sediment Base
4. Interpret the sediment base using the same methods as for the seafloor.
5. When you are finished with both horizons, click the Close button.

Interpreting with auto-tracking:

1. To select Snap mode look at the seismic display and identify the reflector representing the seabed. Compare the color of the seabed reflector with the seismic color table. The color on the left side of the color table represents minima; the color on the right represents maxima. The seismic color table used is one of three:

   1. current active seismic color table – look in the lower right corner of Geocap.
   2. the color table specified in Seismic display, if any.
   3. the color table dragged and dropped on top of the seismic line, if any.
2. Select Snap mode accordingly.
3. Select Track mode to be Auto.
4. Set Delta Z. Delta Z is the maximum allowable vertical distance between two auto-tracked points. Z is usually time in ms. A good rule of thumb is that Delta Z should be the double of the sample interval in the seismic. In our case that is 8.
5. Pick the horizon to autotrack by pressing the <space> or p key on the keyboard
6. The horizon is automatically interpreted
7. If the interpretation stopped at one point press <space> or p again to continue where it stopped.
8. When you are happy with the interpretation click the Image Removed buttono Image Removed

We have now set up everything we need and are ready to start interpreting. Interpreting manually:

1. Click the Image Removed button.
2. Pick points on the seismic line by pointing the mouse cursor on the seismic line and pressing the p or <space> key on the keyboard. If you want to undo a pick, you can press the d key.
3. When you are finished interpreting click the Image Removed button.

Editing an interpretation:

1. Click the Image Removed button.
2. Re-pick points in an area where you have picked points before. You pick points the same way as you did the first time.
3. When you are finished interpreting click the Image Removed button.
4. Observe that the old interpretation is updated with the new interpretation.

Deleting parts of an interpretation:

1. Click the Image Removed button.
2. Pick two points: the start- and the end point of the part of the interpretation that you want to delete.
3. The part of the interpretation between the two points is automatically deleted.

Interpreting with insertion (semi-auto):

1. Keep the Snap mode to be same as you used before.
2. Select Track mode to be Insert
3. Set Interval to 5. This will interpret a point at every fifth trace.
4. Click the Image Removed button.
5. Pick a point on a strong reflection (for example the seabed).
6. Pick a new point a bit to the side, on the same reflection. Observe that auto tracker automatically interprets the line.
7. When you are finished interpreting click the Image Removed button.
8. Observe that the old interpretation is updated with the new interpretation.