Description
Convert length and area independently and divide physicalLength by physicalArea.
Geomorphic geometry uses lengths, areas, volumes, and dimensionless shape ratios to summarize a feature. Grain axes, channel dimensions, and angular units need explicit definitions because similar field names can describe different measurements.
Convert length and area independently and divide physicalLength by physicalArea.
When to use this tool
Use Drainage Density Map Length Area Factor when you need a geometric summary of a supplied landform or sediment measurement.
How to use the tool and how it works
- Enter mappedLength, lengthScale, mappedArea, areaScale. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read physicalLength, physicalArea, drainageDensity. Use the output convention below.
Require nonnegative mappedLength and positive lengthScale, mappedArea, and areaScale. Convert length and area independently and divide physicalLength by physicalArea.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| mappedLength | Mapped Length | Required. Finite number; minimum 0. |
| lengthScale | Length Scale | Required. Finite number; strictly above 0. |
| mappedArea | Mapped Area | Required. Finite number; strictly above 0. |
| areaScale | Area Scale | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| physicalLength | Physical Length | Required. Finite number. |
| physicalArea | Physical Area | Required. Finite number. |
| drainageDensity | Drainage Density | Required. Finite number. |
{
"input": {
"mappedLength": 10,
"lengthScale": 2,
"mappedArea": 5,
"areaScale": 4
},
"output": {
"physicalLength": 20,
"physicalArea": 20,
"drainageDensity": 1
}
}Limitations and assumptions
- LengthScale is physical length per map length and areaScale physical area per map area; area conversion is not automatically the square of the length factor and no actual map coverage is verified.
- 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 the measured feature and sampling method for the intended geometric definition. Use a spatial model or complete distribution when a single shape ratio or local term is insufficient.
References
Similar or alternative tools
- Beach Profile Trapezoid Area Term
Return their width and width times the average endpoint height relative to referenceHeight as signedArea.
- Relief Ratio Basin Length Term
Return relief and relief/basinLength.