Detecting new surfaces

A new surface can be detected on acoustic multibeam variables. The detection is performed using settings from the Surface Detection tab of the EV File Properties dialog box with the Multibeam bottom detection algorithm. The detection supports a transducer with an elevation that lies between 0 to 90°. Elevations with components that point upwards are not handled by the detection.

• Multibeam bottom preview
• Surface tool
• Dataflow window
• View surface
• Notes

Multibeam bottom preview

You can preview bottom samples used in the surface detection.

Surface tool

To detect a surface on an active multibeam echogram:

1. Click the Surface tool arrow .
2. Select New Surface ...
3. On the New Surface dialog box, enter a name for the surface, enter other settings and specify Properties detection settings as required.
4. Click OK.
5. A surface object appears on the Dataflow window.

Dataflow window

To detect a surface on a multibeam acoustic object:

1. On the Dataflow window click a multibeam acoustic variable.
2. On the Shortcut menu, select New, Create new object via Dataflow Toolbox.
3. On the Dataflow Toolbox, under Lines and Surfaces, select a Surface pick from current variable, drag and drop it onto the Dataflow window. A surface object appears on the Dataflow window.
4. On the New Surface dialog box configure the Destination, Source and Visibility Properties.
5. Click OK.

Notes:

• You can click and drag node arrows between surfaces in the Dataflow window to update a virtual surface’s input operand.

View the surface

• Add the surface object to a scene, see About the Scene window.
• View the line on a multibeam ping that represents a surface-ping intersection, see the Surfaces page of the Variable Properties dialog box.

Notes

• You can only detect a surface if GPS data are available. As a result, surface-ping intersections may not appear in some pings.
• To achieve the best results for a detected surface, echogram data should be tightly transected.
• A 3D object surface has Properties where the name and appearance can be edited and details about the object are available.
• You can resample a 3D bottom surface with a different resolution using the Resample Surface dialog box.
• If the detected surface appears unusual please refer to known 3D surface detection problems.
• A detected surface can be exported as a 3D object.
• The preview bottom sample data that are used for the detection can be exported.
• Surface detection may be affected by the Exclusions and/or Surface exclusion settings on the Analysis page.

See also

Multibeam bottom detection algorithm