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Experiences from the post processing of typical Finnish bathymetric data

Experiences from the post processing of typical Finnish bathymetric data. Jarmo Ahonen. Shallow Survey 2008 Portsmouth, NH. Agenda. Survey vessels and survey environment Workflow Qinsy Qlucheck Fledermaus CUBE S2Edit Examples Conclusions from our experiences. Multibeam vessels.

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Experiences from the post processing of typical Finnish bathymetric data

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  1. Experiences from the post processing of typical Finnish bathymetric data Jarmo Ahonen Shallow Survey 2008 Portsmouth, NH

  2. Agenda • Survey vessels and survey environment • Workflow • Qinsy • Qlucheck • Fledermaus • CUBE • S2Edit • Examples • Conclusions from our experiences

  3. Multibeam vessels • Airisto, M249 (SB 7125) • M620, M640, Kaiku (SB 8101) • Suunta (SB 8111)

  4. Single beam vessels • M145, M146, M148, M247 (NS 2000) • Kieku 2 (NS 110) • M101, M216 (NS 50)

  5. Mother ship • Saaristo

  6. ”The most beautiful archipelago in the world” ”The land of the thousands of lakes”

  7. Agenda • Survey vessels and survey environment • Workflow • Qinsy • Qlucheck • Fledermaus • CUBE • S2Edit • Examples • Conclusions from our experiences

  8. Workflow • Qinsy Online • db • qpd • Analyzer • heading/pitch/roll/heave • positioning • Processing Manager • SVP • Tide • ASCII export • Validator • depth blocking • sector blocking .db .qpd • Qlucheck • ASCII to FAU .fau • S2 Software • Contouring • Area based analysis/cleaning • Data thinning • Fledermaus • Area Based Cleaning • CUBE • Unload to fau • Qlucheck • 15/50 million points/block .fau .fau .s2d Orderer = FMA

  9. QINSy Online • .db, .qpd QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  10. Analyzer • Check the motion sensor data and positioning if notice in the logbook QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  11. Processing Manager • Applying Tide and SVP QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  12. Validator • Points flagged by Depth and Sector blocking are not in the next post processing steps • Limiting opening angle to avoid bad data QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  13. Processing Manager • Export user defined ASCII • Easting, Northing, Depth, Ping ID, Beam ID, Quality • 1467111.420 6614994.110 -37.05 1 43 11 • 1467111.840 6614994.180 -37.05 1 44 15 QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  14. Qlucheck • FMA software • Format converter • ASCII to FAU • Quality value is needed in importing to Fledermaus • brightness and collinearity flags • Ping ID and Beam ID is needed in splitting the FAU files QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  15. Fledermaus • Custom filters • Brightness and collinearity flagged points are set to rejected in import • CUBE parameters • Bin size: 1 m • Capture Distance: 5 % of depth • Hypothesis resolution algorithm: Number of Samples + Neighborhood • Calculate errors using sensor specific error model • Area based editing • Clean the outliers first QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  16. Shallow edited surface • A lot of spikes in the data QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  17. CUBE edited surface • Still some spikes in the data • Selected area in focus in 3D Editor QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  18. <= Points colored by survey lines Points and hypothesis => <= Set hypothesis to shallowest points QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  19. <= Raw data <= Unedited CUBE surface Hypothesis set to shallowest points => QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  20. CUBE Filter • Filter soundings based on CUBE surface • 4x standard deviation QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  21. Qlucheck • Split FAU files • .S2D file size limit 50 (15) million points QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  22. S2Edit • FMA software • Are based editing in 2D/3D • Lasso tool • Contour view in 2D/3D • Point view in 2D/3D • Swath view in 2D/3D • DTM model view in 2D/3D • Numerical view in 2D/3D QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  23. Min and max values in 3D • Depth contours give an indication where to focus QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  24. Easy to see typical outliers like aquatic vegetation, sonar errors, fishes • Overlap areas • Colored by survey lines QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  25. Depth contour view • check the suspicious targets • check the shallowest areas • Swath view • check if the target is in the overlapping area • Numerical view • take a closer look QINSy Online • Processing Manager • Validator Analyzer Qlucheck Fledermaus Qlucheck S2Edit

  26. Agenda • Survey vessels and survey environment • Workflow • Qinsy • Qlucheck • Fledermaus • CUBE • S2Edit • Examples • Conclusions from our experiences

  27. Example 1 • Outliers cleaned before CUBE filter (4x std dev.) • Contours are smooth • Swath view shows that CUBE filter succeeded

  28. Example 2 • Outliers not cleaned before CUBE filter (4x std dev.) • Contours are mainly smooth • Outlier contours inside the boxes • Clear outliers still exists

  29. Example 2 • SB7125 produces a lot of outliers • Outliers should be cleaned before CUBE filtering

  30. Example 3 • Shallowest points in the region are the most important points • Blue point is shallowest and accepted • Red points are rejected • CUBE filters also points which are real sea bed • FMA does not accept this

  31. Conclusions • Every post processing software has pros and cons • There are no automatic algorithms that can clean challenging sea beds satisfyingly in Finnish environment • SB7125 produces a lot of data and a lot of outliers • CUBE reduces manual editing • CUBE works better in relatively flat sea bottoms • Good work in the survey situation significantly reduces the post processing work

  32. Agenda • Survey vessels and survey environment • Workflow • Qinsy • Qlucheck • Fledermaus • CUBE • S2Edit • Examples • Conclusions from our experiences

  33. Thank you! M.Sc. Jarmo Ahonen jarmo.ahonen@fma.fi

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