Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.
-
Upload
elijah-park -
Category
Documents
-
view
215 -
download
0
Transcript of Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.
![Page 1: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/1.jpg)
Long-term bathymetry changes
Quest4D
Job Janssens – Flanders Hydraulics Research
![Page 2: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/2.jpg)
• Available data• Interpolation
concerns
methodology
results
• Analysis of the gridsvisualization of the depth lines
trend analysis
chart differencing
conclusions
Outline
![Page 3: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/3.jpg)
Available data
Selection of historical navigation charts:(charts available at Hydrography Department, Flemish Authorities)
2007 chart high resolution grid (20m x 20m)
other charts irregular pattern of data points
![Page 4: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/4.jpg)
Example:Chart of 1938
Available data
![Page 5: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/5.jpg)
Example:Chart of 1938
datapoints 1938 digitized in ArcGIS
Available data
![Page 6: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/6.jpg)
Example:Chart of 1938
datapoints 1938 digitized in ArcGIS
datapoints 1908 digitized in ArcGIS
Available data
![Page 7: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/7.jpg)
Example:Chart of 1938
datapoints 1938 digitized in ArcGIS
datapoints 1908 digitized in ArcGIS
different charts have datapoints on different locations
interpolation of each set of datapoints to a grid
Available data
![Page 8: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/8.jpg)
ArcGIS interpolation techniques:
IDW
kriging
natural neighbor
Problems associated with interpolation:
are averaging techniques
average value cannot be greater than highest or less than lowest input
in sparse data sets:
interpolation cannot reproduce ridges or troughs!
seafloor morphology flattened by interpolation
Interpolation: concerns
![Page 9: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/9.jpg)
“straightforward” interpolation: test case
• 2007 data point set: - high resolution (20m x 20m) - no interpolation needed
Interpolation: concerns
![Page 10: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/10.jpg)
“straightforward” interpolation: test case
• 2007 data point set: - high resolution (20m x 20m) - no interpolation needed
• subset of the 2007 data point set
Interpolation: concerns
![Page 11: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/11.jpg)
“straightforward” interpolation: test case
• 2007 data point set: - high resolution (20m x 20m) - no interpolation needed
• subset of the 2007 data point set
• interpolation of this subset
Interpolation: concerns
![Page 12: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/12.jpg)
“straightforward” interpolation: test case
difference chart: 2007 - 2007 interpolated
• ridges less higher than they are• troughs less deeper than they are
Conclusion:
interpolation of sparse data set flattens morphology
interpolation error correlated with location
Interpolation: concerns
![Page 13: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/13.jpg)
Solution: use high resolution data of 2007 to estimate interpolation error
Example: grid of 1938
grid of 1938 = interpolation of data points 1938
interpolation of sub- set data points 2007
grid of 2007_
Interpolation: methodology
_
estimation of inter- polation error
! Basic assumption:
data points of 2007, but only at locations of the 1938 data points
stable morphology: no major changes in location of ridges/troughs
![Page 14: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/14.jpg)
Interpolation: illustration methodology
![Page 15: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/15.jpg)
Interpolation: illustration methodology
![Page 16: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/16.jpg)
Interpolation: illustration methodology
![Page 17: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/17.jpg)
Interpolation: illustration methodology
![Page 18: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/18.jpg)
Interpolation: illustration methodology
![Page 19: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/19.jpg)
Interpolation: illustration methodology
![Page 20: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/20.jpg)
Interpolation: illustration methodology
![Page 21: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/21.jpg)
Interpolation: illustration methodology
![Page 22: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/22.jpg)
1866
Interpolation: results
![Page 23: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/23.jpg)
1908
Interpolation: results
![Page 24: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/24.jpg)
1938
Interpolation: results
![Page 25: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/25.jpg)
1969
Interpolation: results
![Page 26: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/26.jpg)
2007
Interpolation: results
![Page 27: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/27.jpg)
1) visualization of different depth lines
2) trend analysis
3) chart differencing
Erosion/sedimentation patterns studied through:
Analysis of the grids
![Page 28: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/28.jpg)
1) visualization of depth lines:
Analysis of the grids
Example: Middelkerkebank, 8m depth lines
![Page 29: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/29.jpg)
2) Trend analysis:
Analysis of the grids
linear least square fit on time series of depth values
sedimentation trend
~ 0.03 m/year
(time series of 5 depth values for each grid cell)
![Page 30: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/30.jpg)
2) Trend analysis:
Analysis of the grids
![Page 31: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/31.jpg)
3) Chart differencing:
Analysis of the grids
![Page 32: Long-term bathymetry changes Quest4D Job Janssens – Flanders Hydraulics Research.](https://reader035.fdocuments.in/reader035/viewer/2022062423/5697bf781a28abf838c819ec/html5/thumbnails/32.jpg)
Conclusions:
Analysis of the grids
Morphologic changes:
• Anthropogenic:
dredging: of navigation channels (Scheur, Pas van ‘t Zand)
dumping: S1 (Sierra Ventana), …
influence of breakwaters Zeebrugge harbour: bay of Heist
• Natural:
no significant movement of the banks sedimentation/erosion: coastal banks form the most dynamic zone
sedimentation of the ridges (e.g. Oostendebank)
erosion of the troughs (e.g. Grote Rede, Kleine Rede)