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. The Grid Bathymetry Interpolation and Download Online Bathymetry options are shown in Figure 1 and their use is described below.
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- Grid Layer : is the name of the selected grid layer that we will interpolate its bathymetry.
- Using Visible Data: is the number of data points. In this case, there are 2234 points from the cross-section file.
- Interpolation Options: There are two options, including Update Missing Only (update elevation values for the missing grid nodes only, in case other nodes already have elevation values) and Overwrite All Data (create new elevation values for all grid nodes and overwrite the nodes that have existing elevation values).
- Interpolation Method: the Inverse Inverse Distance Weighting (IDW) is used. The IDW Options frame allows changing its properties.
Click the Interpolate button to proceed interpolation process, when . When it is done, click the OK button to close the form.
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Suppose that there are two cross-sections loaded as shown in Figure 16.. Next, generate a grid that covers the two cross-sections. Note that the grid should have high resolution (grid cells).
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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 2127790207. 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 15 Figure 15
Figure 15 Download online data for bathymetry.
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