Page Comparison

Display stacking velocities

1. Right click the folder Survey03 in 06_Velocities and select Zoom to Folder
2. In the Survey03 folder right click S3_01 and select Map Data. Observe that the velocities are mapped as line.
3. Clear your screen by clicking the icon on the toolbar.
4. Right click S3_01 and select Make bands of velocity and map. Observe that that it is now mapped solid.
5. Try different display commands on the various velocity data sets like; Display survey lines, Display top points and Display top and bottom line

Appending stacking velocity into one file

1. Select the folder Survey03 and in the Toolbox execute the Append all lines in a folder under Schema Commands. The result is stored as appendedData in workspace.
2. Create an temporary folder in your project 
3. Right click the temporary folder and select New > Workspace Data > appendedData
4. Rename the dataset to appendedSurvey03.
5. Select the folder Survey04 and in the Toolbox execute the Append all lines in a folder under Schema Commands. The result is stored as appendedData in workspace.
6. Move appendedData into your temporary folder and rename it to appendedSurvey04
7. Now select your temporary folder and in the Toolbox execute the Append all lines in a folder under Schema Commands. The result is stored as appendedData in workspace.
8. Right click the 06_Velocities folderand select New > Workspace Data > appendedData
9. In the 06_Velocitiesrename the appendedData to all_lines.
10. Right click all_lines and select Map Data
11. Delete the temporary folder.

Digitize a border line for the cube.

1. Set the graphics window in 2D mode.
2. In the 01_Cultural / Boundary folder display border_line
3. On the main menu select Tools > Quick Digitizing
4. In the menu that pops up check the Save digitized line also in folder box
5. Click the Browse button, select the 01_Cultural / Boundary folder and click OK
6. Click Start digitizing
7. Digitize a polygon around the displayed border_line by clicking the left mouse button. When getting to the end, click Connect to start.
8. Click Stop digitizing
9. Close the Quick Digitizer by clicking on the X
10. In the 01_Cultural / Boundary folder rename digitized_line to cube_border.
11. Set the graphics window back into 3D mode.

Grid stacking velocity into a cube.

1. Right click all_lines in the 06_Velocity and select Cube gridding from stacking velocities.
2. Select correct attribute by clicking Set. The combobox should shift to Scalar. Sometimes the velocity is the field data velocity, but in this case it is in the scalar part.
3. Set the Grid window to xmin = -188000, xmax = -47500; ymin = 7864500, ymax = 7959000, zmin = 0, zmax = 6000.
4. Set the cube increments to 500 500 50 which is an acceptable resolution in our case.
5. Click Expand to expand the cube window a little bit to avoid edge effects when depth converting.
6. In our case the size of cube is now 286 194 121.
7. Go to the Grid Options tab.
8. Click Use reference grid or outline and browse in cube_border.
9. Go to the Cube Options tab
10. Check the Apply base grid box 

11. Click the Browse button and select the 01Seabed_time grid in the 06_Velocity folder and click OK
    

    Note
    A base grid decides where the values from the stacking velocities start. Everything above the base grid will get the values from the water velocity, and so the 01Seabed_time is the natural base grid. Note that the grid window and x y grid increments for the base grid must be exactly equal to the cube.

12. Go to the Result Cube tab. Observe that the result cube by default is written back to the same folder as the input.
13. Go to the Testing tab.
14. Drag the slider bar and set the z value to around 2500
15. Click Make velocity grid to perform a test for that level.
16. If everything is OK click Execute to generate the velocity cube. It will be saved as all_lines time_velocity.

Display the whole velocity cube

1. In the 06_Velocities folder right click all_lines_time_velocity and select Cube views > Map boundary surface
2. On the toolbar click and click on the cube in the graphics window.
3. In the menu that pops up adjust the Opacity slider and click Close.
4. Display one of the time grids and observe that it is inside the cube.

Displaying the velocity cube with the manipulator

1. In the folder 06_Velocities right click all_lines time_velocity and select Utilities > Manipulator cube display.
2. Draw the manipulator in all directions by checking Frame and then X, Y or Z.
3. Click the Line contours button to draw contours for each layer.

Displaying different iso contours from the cube.

Iso contours is a direct way to see the interior of the cube. If too noisy one should consider smoothing the cube.

1. Right click all_lines time_velocity and select Cube contours
2. In the menu that pops up type in 2000in Value according to contour level type and click Display at the bottom of the menu
3. Now type in 3000 and click Display
4. Then type in 3800 and click Display
5. Click Cancel on the menu

Evaluate if it is noisy. In that case smooth the cube.

Smoothing a velocity cube

1. Right click all_lines time_velocity and select Smoothing cube
2. In the menu that pops up click the Browse button, select the 06_Velocities folder and click OK
3. Keep default settings and click OK
4. Re-display the iso contours from the smoothedCube