# Integration line algorithm

The Integration line is an on screen analysis that displays the normalized cumulative NASC for pings from left to right, in the analysis domain, of a selected Integration line rectangle (Integration rectangle). The slope of this line provides a visual cue about the nature of the contribution of NASC to pings.

The Integration line settings on the Echogram Display page of the Variable Properties dialog box define the color of and the rectangular area over which the Integration line is evaluated and displayed. The Integration line is affected by changes in data, the analysis domain and Integration rectangle. Such changes can occur on the:

- Grid page of the Variable Properties dialog box
- Analysis page of the Variable Properties dialog box
- Data page of the Variable Properties dialog box

To display an Integration line on an active Sv echogram

- On the
**Echogram**menu select**Variable Properties.**- OR -

Press**F8**. - Select the
**Echogram Display page.** - Click the
**Integration line**arrow to select the desired Integration rectangle. - Click the
**Integration line**colored square to select the desired Integration line color.

**Note:** Sometimes it can take a long time to display the Integration line; especially if there are many small cells. Press ESC to stop the calculation/display of an Integration line.

## Integration rectangle

The Integration rectangle is selected on the Echogram Display page of the Variable Properties dialog box. The Integration line is displayed in the Integration rectangle as follows:

where:

The Integration line starts from the lower left hand corner and ends at the upper right hand corner.

The integration rectangle extends over 0 £ p £ n, where:

0 is the first ping in the integration rectangle

n is the last ping in the integration rectangle

p is a ping in the integration rectangle

## Integration line algorithm

Normalized cumulative NASC at ping p is calculated as:

where:

PRC_NASCp is the PRC_NASC where the analysis domain is the rectangle defined by the pings 0 to p in the Integration rectangle NASCr is the NASC where the analysis domain is the Integration rectangle (containing pings 0 to n)