| Tool Name | Morphometric Features |
| Tool ID | 23 |
| Library ID | ta_morphometry |
| Version | 1.0 |
| Author(s) | O.Conrad (c) 2013 |
Please cite SAGA whenever you use it for your publications:
doi:10.5194/gmd-8-1991-2015
Description
The tool uses a multi-scale approach by fitting quadratic parameters to any size window (via least squares) to derive morphometric terrain parameters like slope, aspect and curvatures. These can be used for subsequent classification of morphometric features (peaks, ridges, passes, channels, pits and planes). This is the method as proposed and implemented by Jo Wood (1996) in LandSerf and GRASS GIS (r.param.scale).
The following datasets can be computed:
- Morphometric features is the terrain classification.
- Generalised elevation is the smoothed input DEM.
- Slope is the magnitude of maximum gradient. It is given for steepest slope angle and measured in degrees.
- Aspect is the direction of maximum gradient.
- Profile curvature is the curvature intersecting with the plane defined by the Z axis and maximum gradient direction. Positive values describe convex profile curvature, negative values concave profile.
- Plan curvature is the horizontal curvature, intersecting with the XY plane.
- Longitudinal curvature is the profile curvature intersecting with the plane defined by the surface normal and maximum gradient direction.
- Cross-sectional curvature is the tangential curvature intersecting with the plane defined by the surface normal and a tangent to the contour - perpendicular to maximum gradient direction.
- Minimum curvature is measured in direction perpendicular to the direction of of maximum curvature.
- The maximum curvature is measured in any direction.
Parameters
| Name | Type | Identifier | Description | Constraints |
|---|
| Input |
|---|
| Elevation | grid, input | DEM | | |
| Output |
|---|
| Morphometric Features | grid, output, optional | FEATURES | | |
| Generalized Surface | grid, output, optional | ELEVATION | | |
| Slope | grid, output, optional | SLOPE | | |
| Aspect | grid, output, optional | ASPECT | | |
| Profile Curvature | grid, output, optional | PROFC | | |
| Plan Curvature | grid, output, optional | PLANC | | |
| Longitudinal Curvature | grid, output, optional | LONGC | | |
| Cross-Sectional Curvature | grid, output, optional | CROSC | | |
| Maximum Curvature | grid, output, optional | MAXIC | | |
| Minimum Curvature | grid, output, optional | MINIC | | |
| Options |
|---|
| Scale Radius (Cells) | integer number | SIZE | Size of processing window (= 1 + 2 * radius) given as number of cells | Minimum: 1
Default: 5 |
| Slope Tolerance | floating point number | TOL_SLOPE | Slope tolerance that defines a 'flat' surface (degrees) | Default: 1 |
| Curvature Tolerance | floating point number | TOL_CURVE | Curvature tolerance that defines 'planar' surface | Default: 0.0001 |
| Distance Weighting Exponent | floating point number | EXPONENT | Exponent for distance weighting (0.0-4.0) | Minimum: 0.000000
Maximum: 4.000000
Default: 0 |
| Vertical Scaling | floating point number | ZSCALE | Vertical scaling factor | Default: 1 |
| Constrain | boolean | CONSTRAIN | Constrain model through central window cell | Default: 0 |