Coverage Extinction Plot option from Tools->Utilities menu of Main Menu bar
What it Does
This tool lets you assess the swath coverage capabilities of your multibeam system.
General Description
Data to fuel this type of plot usually consists of a set of survey lines running from the shallowest to deepest depth range of the system. As the depth increases, the outermost beams will experience increased difficulty with detection, and the coverage will continue to decrease until even nadir beams can no longer detect the bottom. Having this type of plot capability is very useful during Sea Acceptance Trials so the surveyor can assess the system's swath coverage performance relative to the manufacturer's claimed specifications to ensure compliance. It can also help call attention to sources of noise due to mechanical, acoustic or electrical sources of interference. Repeating these types of field trials before and after visits to ship yards can illuminate issues early on, considering mechanical and electrical changes are often made during dry dock periods. For instance, modifications to the hull made in dry dock can can create flow noise problems. Many examples of this type of plot being used to assess and diagnose system health can be seen in the technical reports produced by the Multibeam Advisory Committee (MAC) : http://mac.unols.org/reports.
The image above repeats the analysis of a Kongsberg EM710 data set done by the MAC during a sea trial aboard R/V Falkor (Fall Report 2014, p 18). The graph indicates that the EM710 achieved maximum swath width at a depth of about 500 - 600m, which is within expectation. Full extinction occurred near 2,000m, which was also expected. As with all Qimera plotting widgets, the graph can be saved as a report quality PNG file with full markup of axes, etc.
For more information on navigating the data of the plot, see the section on Qimera Plot Grids.
Toolbar
Zoom Out Button
If you have zoomed into an area of the plot, this button will zoom out to the extents of the data.
Explore Mode
This is the primary exploration mode of the tool. As you move your cursor over the plot, the label in the lower left of the window will update to show the X/Y axis values.
Zoom Mode
When in zoom mode, simply click and drag an area of the plot to zoom into. Or simply single click a location to zoom in a bit on it. Alt-click a location to zoom out a bit. Or hit the Home button to return to the full extents of the data. At any time, you can Shift-Click to drag the plot to a new location. This is especially useful when you are zoomed in.
Plot Point Size
Clicking this icon will change the point size drawn in the widget. If you click and hold the button, it will display a menu where you can select point sizes between Small and XX-Large. Simply clicking will cycle through all sizes.
Plot Color By
Clicking this icon will change the Color By mode of the points drawn in the widget. If you click and hold the button, it will display a menu where you can select the Color By option directly. The options for color by are Vessel, Line, System, Ping Counter (File Unique Ping Identifier), Ping Number (Source Ping Identifier), Beam, Depth, Intensity, Horizontal TPU and Vertical TPU.
Menu
Save to Image
Saves the current plot to a PNG or JPEG file. The image will include all grid lines and annotations labels.
Show Grid Lines
This option will turn grid lines on/off in plot plot area.
