An analysis domain defines the initial set of data points (samples or single targets) that are available for analysis. Analysis domains can take the form of:
Analysis domains can be defined on single beam echograms, single target echograms and scenes.
Note: Analysis is affected by the settings defined on the Analysis page of the Variable Properties dialog box.
The topics discussed on this page include:
Data points with time/distance or depth coordinates that are inside the boundary of the analysis domain are included in the analysis domain.
Data points with time/distance or depth coordinates that place them on a boundary of the analysis domain are treated as follows:
If the data point is on the... 
Then... 
Upper boundary 
it is included in the analysis domain 
Lower boundary 
it is not included in the analysis domain 
Left boundary 
it is included in the analysis domain 
Right boundary 
it is not included in the analysis domain 
Notes:
Created, detected or virtual surfaces may be used as boundaries to include data points for detections and analysis. Data points inside the boundary are included. Data points outside and on the boundary are excluded.
Analysis domains on scenes take the form of 3D regions.
Data points are included in an analysis domain if:
Data points with latitude, longitude and depth coordinates that place them on the boundaries of the analysis domain are highly unlikely to occur and inclusion is undefined in this circumstance.
Data points can be excluded from analysis domains on scenes with the usage of Exclude above and Exclude below surfaces.
Data points (samples or single targets) that are included in an analysis domain are then retained or discarded for further analysis based on the settings defined on the Analysis page. The content of this section may benefit from the topics and background covered by About samples and echo integration.
Data points are excluded from further analysis if they are:
Data points (samples or single targets) are treated as no data if they are:
These samples are assigned a value of no data and they have no sample thickness. In effect, such samples are not counted in the calculations of Thickness_mean and Height_mean. See also the special case below.
Selecting Apply bad data regions also affects:
Samples within a Bad data (no data) region or with a value of no data in concert with the selection of the Analysis page settings Apply bad data regions and Include the volume of nodata samples.
These samples are assigned a value of no data and have a sample thickness. The sample thickness is included in calculations of the Thickness_mean and Height_mean. The settings can affect both entire pings and parts of pings. The key intent of this special case is the robust assumption (in the absence of any further information) about samples in Bad data (no data) regions. You are assuming, in effect, that these samples have a backscatter value equal to the mean of the good samples in the domain.
Prior to Echoview 5.4 it has always been possible to make this (commonlydesired) assumption by scaling the reported Thickness_mean of the domain (and hence the NASC) using the various analysis domain analysis variables (no_data_samples etc.).
Use Apply bad data regions 
Use Apply bad data regions Use Include volume of no data samples 

Hatching cue, Outcomes, Assumptions 
Hatching cue, Outcomes, Assumptions 


Purple border, grey hatch. 
Purple border, grey hatch. This data effectively is converted to the mean of the analysis domain. This gives you greater flexibility in calculating your NASC based results. 


Green hatch. This data is deemed to have no acoustic return. 
Green hatch. This data is deemed to have no acoustic return. 

Red hatch. Good samples used in analysis calculations. 
Red hatch. Good samples used in analysis calculations. 
Data points in intersections of regions or other designated areas may change in nature, for calculation purposes, according to an order of precedence:
With the Good category being dominated by any of the following categories, and the Below Exclude below line category dominating any of the preceeding categories.
The Processed data operator can often make clear how samples are affected by Analysis page settings.
The screeshot to the right shows region types, integration cues and intersections. Regions include:

Data points that are included in an analysis domain are then retained or discarded for further analysis based on the settings defined on the Analysis page.
Data points are excluded from further analysis if they are:
Excluded data points are ignored for these primary calculations:
In turn, these quantities variously affect the calculation of:
Notes:
The data points that are included in an analysis domain and not subsequently excluded are known as good data points.
When you perform an onscreen integration or an onscreen analysis of an analysis domain, all good data points will be overlayed with analysishatching (providing that the Show Analysis option on the Echogram page of the EV File Properties dialog is selected).
You can view the good data points for an entire echogram using the Processed Data operator. This operator assigns a value of no data to excluded data points.
You can view information about a data point as follows:
To view time information about a data point, move the mouse point over the data point and check the status bar.
To view depth and range information about a data point display the Details dialog box (F9).
About analysis
About analysis variables
Samples
About integration
About samples and integration
About no data
Thickness mean and Height mean
ABC and NASC
About biomass estimation
About single targets
About no data
Sv_mean
Analysis page
Bad data regions
Special data values