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The parameters are set in the four tabs: Shoals/Deeps, Saddles, Ridges and Valleys
The Shoals/Deeps
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tab
Shoals search radius detection
Will find those grids nodes that are the shallowest within the Minimum distance.
The option Mask width is a mask moving over the grid and checking the centre node with the nodes around.
A shoal is detected when the centre node is shallower than the rest of the nodes in the mask. After the detection the points are sorted on increasing depth values, and by starting with the first (and shallowest) point, all points with a distance smaller than the Minimum distance will be removed. Then the same test is performed for the next valid point, etc.
The shoals are saved in <chart name> classification shoals_<filter width>_<distance>.
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Deeps search radius detection
Will find those grids nodes that are the highest within the Minimum distance.
The option Mask width is a mask moving over the grid and checking the centre node with the nodes around.
A deep is detected when the centre node is deeper than the rest of the nodes in the mask. After the detection the points are sorted on decreasing depth values, and by starting with the first (and deepest) point, all points with a distance smaller than the Minimum distance will be removed. Then the same test is performed for the next valid point, etc.
The deeps are saved in <chart name> classification deeps_<filter width>_<distance>.
Find corresponding Shoals/Deeps in Soundings
This option enables a search in the Soundings dataset for the nearest point that was found in the Seafloor grid. The corresponding points are saved in <chart name> classification <type>in_soundings<parameter>.
The Saddles tab
Will find those grids nodes that have two low and two high neighbour points.
If the search radius is greater than zero, the lowest saddle point within the search radius
will be selected.
Saved in <chart name> classification saddles_<searchradius>.
The Ridges tab
Will find those grids nodes that define a ridge. The two parameters are the
maximum ridge angle towards the shallow area and the minimum ridge angle towards the deep area.
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To see all ridge points set maximum ridge angle towards the shallow area = 90, and
minimum ridge angle towards the deep area = 0. Default setting is 20 and 5.
Test and tune the parameters to get the proper ridge points.
Saddles
Will find those grids nodes that have two low and two high neighbour points.
If the search radius is greater than zero, the lowest saddle point within the search radius
will be selected.
Saved in <chart name> classification saddles_<searchradius>.
Valleys
The Valleys tab
Will find those grids nodes that define a valley (which is the opposite of a ridge).
The two parameters are the
maximum valley angle towards the deep area and the minimum valley angle towards the shallow area.
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To see all valley points set minimum valley angle towards the deep area = 0, and
maximum valley angle towards the shallow area = 90. Default setting is 5 and 20.
Test and tune the parameters to get the proper valley points.
Find corresponding points in Soundings
This option enables a search in the Soundings dataset for the nearest point that was found in the Seafloor grid. The corresponding points are saved in <chart name> classification <type>in_soundings<parameter>.