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Will find those grids nodes that are the shallowest within the Minimum distance. The parameters are:The option
- Mask width
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- : Is a mask moving over the grid and checking the centre node with the nodes around.
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- Default value is 2.
- Minimum distance: 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. Default value is 25.
The shoals are saved in <chart name> / classification / shoals_<filter <mask width>_<distance>.
Deeps search radius detection
Will find those grids nodes that are the highest deepest within the Minimum distance.
The option Mask width is The parameters are:
- Mask width: Is a mask moving over the grid and checking the centre node with the nodes around. Default value is 2.
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- Minimum distance: 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. Default value is 25.
The deeps are saved in <chart name> / classification / deeps_<filter <mask 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>_<mask width>_<distance>.
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 parameters are:
- Mask width (grid cells): A filter moving over the grid and checking the centre node with the nodes around. Default value is 2.
- Minimum depth difference (m):
Will find those grids nodes that have two low and two high neighbour points.
The option Mask width is a filter moving over the grid and checking the centre node with the nodes around.
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 Filter width will be removed. Then the same test is performed for the next valid point, etc.
The result is saved in <chart name> / classification / saddles_<mask width>.
The Ridges tab
Will find those grids nodes that define a ridge. The two parameters are:
- Mask width (grid cells): A filter moving over the
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- grid and checking the centre node with the nodes around. Default value is 2.
- Slope angle towards shallower (deg): The vertical angle towards shallower terrain. This angle should not be too steep for a ridge point. Default value is 2.
- Slope angle towards deeper (deg): The vertical angle towards shallower terrain. This angle should be steeper than the upward angle. Default value is 5.
- Maximum contour angle (deg): The angle of a contour line passing through the selected point. A smaller angle gives a sharper feature. Default value is 120.
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 Mask width will be removed.
The result is saved in <chart name> / classification / ridges_'mask width'_'shallower angle'_'deeper angle'_'contour angle'.
To see all ridge points set maximum ridge Slope angle towards the shallow area = 90, and
minimum ridge angle towards the deep area = 0. Default setting is 20 and 5.shallower = 1, Slope angle towards deeper = 1 and Maximum contour angle = 180.
Test and tune the parameters to get the proper ridge points.
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Will find those grids nodes that define a valley (which is the opposite of a ridge).
The two parameters are:
- Mask width (grid cells): A filter moving over the grid and checking the centre node with the
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- nodes around. Default value is 2.
- Slope angle towards shallower (deg): The vertical angle towards shallower terrain. This angle should be steeper than the downward angle for a valley point. Default value is 5.
- Slope angle towards deeper (deg): The vertical angle towards shallower terrain. This angle should be not be too steep for a valley point. Default value is 2.
- Maximum contour angle (deg): The angle of a contour line passing through the selected point. A smaller angle gives a sharper feature. Default value is 120.
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 Mask width will be removed. Then the same test is performed for the next valid point, etc.
The result is saved in <chart name> / classification / valleys_'maskwidth'_'shallower angle'_'deeper angle'_'contour angle'.
To see all valley points set minimum valley set Slope angle towards the deep area = 0, and
maximum valley angle towards the shallow area = 90. Default setting is 5 and 20shallower = 1, Slope angle towards deeper = 1 and Maximum contour angle = 180.
Test and tune the parameters to get the proper valley points.