Description
Calculate nominal swept area from tow distance, width and supplied coverage fraction.
Fish records distinguish morphometric length definitions, relative image scales, annulus labels, detection times and survey-effort geometry. A supplied conversion factor need not apply across species or sizes. Local labels, ratios and nominal swept areas organize observations without identifying a fish, determining age or estimating abundance.
Calculate nominal swept area from tow distance, width and supplied coverage fraction.
When to use this tool
Use Fish Trawl Swept Area Factor when you already have towDistance, effectiveNetWidth, suppliedCoverageFraction and need to calculate nominal swept area from tow distance, width and supplied coverage fraction.
How to use the tool and how it works
- Enter towDistance, effectiveNetWidth, suppliedCoverageFraction. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read sweptArea. Use the output convention below.
Require nonnegative distance/width and fraction in [0,1]; return distance*width*fraction.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| towDistance | Tow Distance | Required. Finite number; minimum 0. |
| effectiveNetWidth | Effective Net Width | Required. Finite number; minimum 0. |
| suppliedCoverageFraction | Supplied Coverage Fraction | Required. Finite number; minimum 0; maximum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| sweptArea | Distance*width*coverage fraction under a rectangular swath assumption; length units must agree. | Required. Finite number. |
{
"input": {
"towDistance": 1000,
"effectiveNetWidth": 10,
"suppliedCoverageFraction": 0.8
},
"output": {
"sweptArea": 8000
}
}Limitations and assumptions
- Assumes matching linear units and a rectangular effective swath; no path, overlap, catchability, abundance or suitable survey practice is inferred.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect original specimens, images, reference definitions and survey logs when verifying observations. Use a complete species-appropriate measurement or population method for age, abundance or condition questions; local scales and effort terms preserve only their stated basis.
References
Similar or alternative tools
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Estimate total length using a supplied total-per-fork linear factor.
- Fish Tag Release Recapture Date Gap
Measure signed days from tagged-fish release to recorded recapture.