Description
Resolve length into cosine horizontal run and sine vertical rise and return tan(angle) as slope.
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.
Resolve length into cosine horizontal run and sine vertical rise and return tan(angle) as slope.
When to use this tool
Use Dune Slipface Angle Projection when you need a geometric summary of a supplied landform or sediment measurement.
How to use the tool and how it works
- Enter slopeLength, angleRadians. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read horizontalRun, verticalRise, slope. Use the output convention below.
Require nonnegative slopeLength and angleRadians strictly within ±π/2. Resolve length into cosine horizontal run and sine vertical rise and return tan(angle) as slope.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| slopeLength | Slope Length | Required. Finite number; minimum 0. |
| angleRadians | Angle Radians Unit: rad. | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| horizontalRun | Horizontal Run | Required. Finite number. |
| verticalRise | Vertical Rise | Required. Finite number. |
| slope | Slope | Required. Finite number. |
{
"input": {
"slopeLength": 10,
"angleRadians": 0.5235987755982988
},
"output": {
"horizontalRun": 8.660254037844387,
"verticalRise": 4.999999999999999,
"slope": 0.5773502691896257
}
}Limitations and assumptions
- Angle is measured from horizontal in radians and signed rise follows it; the result is ideal geometry rather than a field measurement, stable angle, or dune-process model.
- 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
- Slope Break Angle Difference
Convert each signed rise/run fraction using atan and return second angle minus first and its absolute magnitude in radians.
- Alluvial Fan Radial Slope Term
Divide apexElevation-toeElevation by that distance for gradient and take atan for angleRadians.