The Data menu provides options for bathymetry interpolation as well as accessing online bathymetry data. Being able to view bathymetry underneath the grid helps determine the resolution required in the deep and main channel regions compared to shallow regions, which can often have lower resolutions. In many cases, bathymetry data needs to be interpolated to cover the whole domain. This section describes features unique to Grid+ whereby a user may interpolate between two cross-sections along even over a sinusoidal domain. The Grid Bathymetry Interpolation and Download Online Bathymetry options are shown in Figure 1 and their use is described below.
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Figure 5 Define projection.
Anchor Figure 6 Figure 6
Figure 6 Cross-sections loaded.
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Figure 7 Cross-sections loaded.
Anchor Figure 8 Figure 8
Figure 8 Cross-sections displayed in color ramp.
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The bottom elevation values for the grid are for grid nodes, not for the centroid of grid cells. |
Anchor Figure 9 Figure 9
Figure 9 Grid Bathymetry Interpolation.
Anchor Figure 10 Figure 10
Figure 10 Topographic Interpolation form.
Anchor Figure 11 Figure 11
Figure 11 Grid with bottom elevation.
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RMC on the grid layer and select Show Properties / Bottom Elevation to display the bottom elevation of the grid after its grid nodes are assigned elevation values, as shown in Figure 15.
Anchor Figure 12 Figure 12
Figure 12 Draw a polygon that covers the grid.
Anchor Figure 13 Figure 13
Figure 13 Interpolation by using a polygon.
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Download Online Bathymetry
After selecting the Download Online Bathymetry option, the Download Online Data form will be displayed as shown in Figure 29. Users are able to select data set using the drop-down Data Set. The currently available open-source sites are:
- GEBCO 2021: This is 2021 GEBCO’s gridded bathymetric data set, the GEBCO_2021 Grid, is a global terrain model for ocean and land, providing elevation data, in meters, on a 15 arc-second interval grid. The data information can be found on GEBCO's website GEBCO 2021.
- GEBCO 2014: This is 2014 GEBCO’s gridded bathymetric data set. The data information can be found on GEBCO's website GEBCO 2014.
- GEBCO 08: a continuous terrain model for ocean and land with a spatial resolution of 30 arc-seconds released by the General Bathymetric Chart of the Oceans (GEBCO) in 2009. Bathymetric data is available to download, and the user manual can be found on the website GEBCO 08.
Depending on the data set selected, different data information is provided in the Spatial Information section. The Data Extraction Limits is auto-set to the whole model domain, but the user can manually select the specific area by checking to Using Polygon File and browser to the closed polygon that contains the area inside.
Click on Download button and Grid+ will download and apply the bathymetry data of the selected Data Set to the specific defined area.
Anchor Figure 29 Figure 29
Figure 29 Download online data for bathymetry.
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