The MeanDensityData model data holds the density of individuals as number per square nautical mile, by Stratum and Layer. The data type contains the tables Data and Resolution. The variables of the MeanDensityData are the same as in DensityData, except that the variable PSU is not present in the table Data, and that the variable DensityWeight is replaced by the variable MeanDensityWeight:
Data:
| Variable | Description | Unit | Data type | Example | Occurrence |
| Survey | The survey identifier | None | Character | "MainSurvey" | Always |
| Stratum | The stratum identifier | None | Character | "Stratum1" | Always |
| Layer | The depth Layer identifier | None | Character | "Layer1" | Always |
| Beam | Unique Beam identifier | None | Character | "38000/2" | AcousticDensity |
| SpeciesCategory | The species category | None | Character | "Herring" | Always |
| IndividualTotalLength | Total length (from snout to end of fin), given as the lower end of the interval of width given by LengthResolution | cm | Numeric | 14.5 | SweptAreaDensity |
| LengthResolution | Resolution of IndividualTotalLength | cm | Numeric | 0.5 | SweptAreaDensity |
| Frequency | The acoustic frequency of the Beam | hertz | Numeric | 38000 | AcousticDensity |
| Density | The density, either given as number of individuals or weight per square nautical mile (when DensityType is "AreaNumberDensity" or AreaWeightDensity, respectively) | nmi^-2 if DensityType is "AreaNumberDensity", and kg nmi^-2 if DensityType is "AreaWeightDensity" (only relevant when SweptAreaDensityMethod is "TotalCatch") | Numeric | 123.4 | Always |
| MinLayerDepth | The minimum depth of the depth Layer | m | Numeric | 0 | Always |
| MaxLayerDepth | The maximum depth of the depth Layer | m | Numeric | 100 | Always |
| MeanDensityWeight | The weight of the density value associated with the Stratum, i.e., the number of Stations for SweptAreaDensity and total LogDistance for AcousticDensity | None | Numeric | 8 | Always |
| DensityType | The type of density, currently one of "AreaNumberDensity" and "AreaWeightDensity" | None | Character | "AreaNumberDensity" | Always |
Resolution:
| Variable | Description | Unit | Data type | Example | Occurrence |
| Stratum | The stratum identifier | None | Character | "Stratum1" | Always |
| PSU | The PSU identifier | None | Character | "PSU1" | Always |
| EDSU | Unique elementary distance sampling unit (EDSU/Log) identifier | None | Character | "2020821/2020-04-24T03:51:26.000Z" | AcousticDensity |
| Station | Unique Station identifier | None | Character | "2021105-1" | SweptAreaDensity |
| Layer | The depth Layer identifier | None | Character | "Layer1" | Always |
| Channel | Unique NASC depth channel identifier | None | Character | "2" | AcousticDensity |
| Cruise | Unique Cruise identifier (see StoxAcousticFormat for output from AcousticDensity and StoxBioticFormat for output from SweptAreaDensity) | None | Character | "2021105" | Always |
| EffectiveLogDistance | The effective length of the EDSU | nmi | Numeric | 0.09 | AcousticDensity |
| EffectiveTowDistance | Effective tow distance of the Haul | nmi | Numeric | 1.5 | SweptAreaDensity |
| DateTime | UTC time at start of the EDSU or Station, stored as POSIXct | ISO8601 | Character | 2020-09-09T01:02:03.456Z | Always |
| Longitude | Longitude at start of the EDSU or Station | degree east | Numeric | 62.5 | Always |
| Latitude | Latitude at start of the EDSU or Station | degree north | Numeric | 5.1 | Always |
| VerticalNetOpening | Vertical span of the net | m | Numeric | 23 | SweptAreaDensity |
| HorizontalNetOpening | Vertical span of the net | m | Numeric | 105 | SweptAreaDensity |
| TrawlDoorSpread | Distance between the trawl doors. | m | Numeric | 125 | SweptAreaDensity |
This data type is produced by MeanDensity based on DensityData See DataTypes for a list of all StoX data types produced by RstoxBase