TZT3 DDF3D PBG issue
- Thread starter brinkis
- Start date
Good afternoon Brinkis,
Thank you for your inquiry.
I am a little confused by the spots concerning the word "Spots" but I think I can work with you to clarify.
Bottom always showing Blue: Based on this, when you are recording PBG in a new area that has not been mapped, the PBG data is always showing the blue color in the center of the swath, or the center of the swath is always deeper than the outside edges of the swath. Is this what you mean by bottom always showing blue?
Typically when the center of the beam is always deeper than the outside edges it means that we need to make sound speed correction. When the speed of sound is not corrected for a multibeam the bottom profile can be a concave shape or a convex shape.
Please see the photo below that highlights this. In the photo the there is a hump in the center rather than a dip in the center. But its the same phenomena that occurs due to incorrect sound speed correction. This can be adjusted in the Multi Sounder Menu in TZ Pro. Typically the way I perform the correction is look at the "Section View" display mode. Then I open the Multi Sounder menu and i adjust the side of the window and move it over just below the bottom of the section view. The window acts like a straight edge, so you can use it to measure the distance from the top of the window to the middle of the bottom profile in the section view. Then you can start to adjust the sound speed correction to make the hump or the dip go away.
Spots- We need a little more work to define what spots mean for your example. Are you talking about Spot Soundings are the depth numbers that are generated on the chart when you have PBG working? I am thinking you are meaning that you are not seeing bumps or structure in the PBG mapping in the middle of the swath but I don't know for sure?
Thank you for your inquiry.
I am a little confused by the spots concerning the word "Spots" but I think I can work with you to clarify.
Bottom always showing Blue: Based on this, when you are recording PBG in a new area that has not been mapped, the PBG data is always showing the blue color in the center of the swath, or the center of the swath is always deeper than the outside edges of the swath. Is this what you mean by bottom always showing blue?
Typically when the center of the beam is always deeper than the outside edges it means that we need to make sound speed correction. When the speed of sound is not corrected for a multibeam the bottom profile can be a concave shape or a convex shape.
Please see the photo below that highlights this. In the photo the there is a hump in the center rather than a dip in the center. But its the same phenomena that occurs due to incorrect sound speed correction. This can be adjusted in the Multi Sounder Menu in TZ Pro. Typically the way I perform the correction is look at the "Section View" display mode. Then I open the Multi Sounder menu and i adjust the side of the window and move it over just below the bottom of the section view. The window acts like a straight edge, so you can use it to measure the distance from the top of the window to the middle of the bottom profile in the section view. Then you can start to adjust the sound speed correction to make the hump or the dip go away.
Spots- We need a little more work to define what spots mean for your example. Are you talking about Spot Soundings are the depth numbers that are generated on the chart when you have PBG working? I am thinking you are meaning that you are not seeing bumps or structure in the PBG mapping in the middle of the swath but I don't know for sure?
If related to the TimeZero PC software, you would want to talk with Nobeltec.
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