Threshold response graph

The Threshold Response graph plots threshold Sv value (X axis) versus the resulting NASC (Y axis) for a selected analysis domain. It can be linked to a selection or region and display the threshold response of a single variable or multiple variables.

To display the Threshold Response graph from an Sv echogram:

  1. On the View menu, point to Graph then click Threshold Response.
  2. On the Threshold Response properties dialog box select the desired variables and settings to configure the graph, then click OK.
  3. On the Graph menu, point to Linking and click the desired type of graph linking for the Threshold Response graph.
  4. Make a selection, or click on a region (on an echogram you selected in step 2) to display the threshold response for your variable(s).


  • When viewing multiple variables it may be useful to use the Synchronize echograms tool.
  • If graph linking is enabled, then the Threshold Response graph will respond only to selections and/or regions on variables which are selected on the Threshold Response graph properties box.
  • A legend can be toggled to display or hide using Shortcut menu, Color Legend. Color legend constraints may mean that not all legend labels are listed.

See also

About graphs
About Linking Graphs
Threshold Response graph properties dialog box