Description
Compare a supplied river gradient with its reference gradient.
Geomorphic measurements distinguish signed coordinates, grain-size scales, profile derivatives and transported-mass or cross-section bases. A supplied datum adjustment or threshold does not detect a landform or establish a process. Plan distance, profile second derivative and slope-normalized curvature are different quantities.
Compare a supplied river gradient with its reference gradient.
When to use this tool
Use River Knickpoint Gradient Residual when checking the stated local landform, sediment, profile or coordinate convention.
How to use the tool and how it works
- Enter observedGradient, referenceGradient. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read gradientResidual. Use the output convention below.
Return observedGradient-referenceGradient as a signed residual using the same rise/run and coordinate convention.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| observedGradient | Observed Gradient | Required. Finite number. |
| referenceGradient | Reference Gradient | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| gradientResidual | Gradient Residual | Required. Finite number. |
{
"input": {
"observedGradient": 0.08,
"referenceGradient": 0.03
},
"output": {
"gradientResidual": 0.05
}
}Limitations and assumptions
- A residual is not a detected knickpoint, fitted river profile or explanation of geomorphic change.
- 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
Use calibrated surveys, mapped geometry and suitable complete sediment/terrain models for trends, process interpretation, uncertainty or hazard assessment.
References
Similar or alternative tools
- Terrain Rise Run Gradient
Calculate signed rise/run gradient and its percentage-grade representation.
- Hillslope Profile Curvature Three Point Term
Calculate a three-point elevation-profile second derivative at equal horizontal spacing.