How to Start
- CUBE sub-menu of the Dynamic Surface menu option in the Main Menu bar
What it Does
The CUBE Filter Soundings dialog lets you reject soundings based on the current CUBE surface.
Soundings that are far enough away from the surface based on selected criteria can be marked as rejected. If you have a good CUBE surface this can help eliminate a lot of noisy data in the selected dynamic surface. The Filtering Method lets you setup this selection criterion. The distance can be based sounding distance from the CUBE surface via several methods including Standard Deviations (actually the CUBE Uncertainty) of the data in a cell, in Meters, or by a combination of both (if either passes then the sounding will be rejected). A second option lets you filter based on the computed IHO Depth Uncertainty whereby the expected maximum uncertainty of a sounding is computed based on the parameters provided and if the soundings uncertainty is larger then that it is a candidate to be rejected. By default these selection criteria are based on a flat surface cell. However if you check the Filter Based on Distance from the regional surface slope then the system will calculate the slope of the of a given cell from the selected hypothesis and some of it's neighboring cell's selected hypotheses. From this slope the distance of each sounding is measured perpendicular to the slope. The calculation is more intensive then the flat surface assumption but generally yields superior results. The calculation is more intensive then the flat surface assumption but generally yields superior results.
You can choose to Apply this filter to only soundings above the surface, only below the surface, both above and below, or select different criteria for above and below. If one chooses different criteria for above and below the CUBE surface you will get two tabs for entering the filtering parameters, one for each.
By default the action is to mark soundings as rejected that are selected by the filter however you can reverse the nature of the filter by telling the algorithm to Clear the rejected flag as well. Sometimes this is useful to run the algorithm on an area, if you over filter then change it to clear the rejected flag and run it again to reverse your filter and try again with new parameters. Note however that clearing the rejection flag could bring back soundings which have been previously rejected by other operations. As well as setting or clearing rejected flag, soundings can be marked as suspect or suspect flags cleared.
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