Description
Flag height-change magnitude strictly above a supplied DEM threshold.
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.
Flag height-change magnitude strictly above a supplied DEM threshold.
When to use this tool
Use Dem Height Difference Threshold when checking the stated local landform, sediment, profile or coordinate convention.
How to use the tool and how it works
- Enter laterHeight, earlierHeight, suppliedThreshold. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read heightChange, exceedsMagnitudeThreshold. Inspect exceedsMagnitudeThreshold before interpreting the associated values.
Require suppliedThreshold>=0. Return later-earlier height and flag only when its absolute magnitude is strictly greater than threshold.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| laterHeight | Later Height | Required. Finite number. |
| earlierHeight | Earlier Height | Required. Finite number. |
| suppliedThreshold | Supplied Threshold | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| heightChange | Height Change | Required. Finite number. |
| exceedsMagnitudeThreshold | Strict abs(change)>suppliedThreshold; equality returns false. | Required. Boolean. |
{
"input": {
"laterHeight": 105,
"earlierHeight": 100,
"suppliedThreshold": 2
},
"output": {
"heightChange": 5,
"exceedsMagnitudeThreshold": true
}
}Limitations and assumptions
- Equality does not exceed the threshold; the criterion is supplied rather than derived from DEM uncertainty, registration error or significance analysis.
- 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
- Hillslope Profile Curvature Three Point Term
Calculate a three-point elevation-profile second derivative at equal horizontal spacing.
- Shoreline Tide Stage Reference Offset
Subtract a supplied horizontal tide-stage offset from a shoreline coordinate.