This analysis variable calculates the sum of the volumes of the analysis domain that were sampled in each ping. Beam_volume_sum can be used for single target analysis. Refer to Beam angle parameters for information about adjusting the Equivalent twoway beam angle for single target analysis.
The beam volume of a single ping within the analysis domain is calculated as:

where
= the twoway beam angle (steradians)  
n

= the number of boundaries, Ri, crossing the ping (). See illustration below.  
=  0 if the interval between Ri and Ri+1 is in the analysis domain and:
Note: Nodata samples may occur in a number of ways (nodata samples, samples within 

1 otherwise, including below threshold data 

R0

= the range (measured along the beam axis of the ping) to the first sample in the analysis domain (m)  
Rn

= the range (measured along the beam axis of the ping) to the last sample in the analysis domain (m) 
Note: Generally, for Single target analysis, the setting Include the volume of bad data (nodata) regions should be unselected.
In the example below the samples in the ranges (R1 to R2), (R3 to R4), and (Rn2 to Rn1) are part of bad data regions and the volume of the beam in these ranges will not be included in the overall beam volume for the ping. The red hatching marks the samples which were analyzed  see analysis hatching for details.
The sum of the beam volumes of all pings in the analysis domain is calculated as:
where:
N = The number of pings in the analysis domain being analyzed
Vp = The volume of ping p  as above (m3)
Notes:
Beam_volume_sum does not necessarily represent the sampled volume of water as the calculation does not take overlap between pings into account. This is of particular note in the case of a fixed transducer where two pings may represent sampling of the same volume of water.
To calculate the average number volume samples by all analyzed pings divide beam_volume_sum by the number of pings in the analysis domain.
This analysis variable was known as Volume_sampled in Echoview 3.00 and earlier and was only available for onscreen single target analyses.
Calculation of Beam_volume_sum assumes that the variable (or echogram) contains individual pings. The results of this calculation will not be valid for resampled, integrated or otherwise reduced pings.
Samples
About analysis domains
Wedge_volume_sampled
About single targets: Analysis
Beam angle parameters