Upslope and Downslope Curvature
- Author: P.Gandelli, O.Conrad (c) 2015
- Menu: Terrain Analysis | Morphometry
Description
This tool first calculates the local curvature of a cell as sum of the gradients (i.e. tangens of slope) to its neighbour cells. This is a simple estimation of the general curvature and is strongly correlated with general curvatures calculated with other methods (e.g. Zevenbergen & Thorne 1987). Then upslope curvature is calculated as the distance and flow proportional weighted average local curvature over a cell's upslope contributing area following the multiple flow direction algorithm after Freeman (1991). In a similar way the downslope curvature is calculated by summarizing the curvatures of all hydrologically downslope connected cells. The local upslope/downslope curvatures just take the immediately neighboured cells into account.
References
- Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22. ScienceDirect.
- Zevenbergen, L.W., Thorne, C.R. (1987): Quantitative analysis of land surface topography. Earth Surface Processes and Landforms, 12: 47-56. Wiley Online Library.
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Elevation | grid, input | DEM | - | - |
| Output | Local Curvature | grid, output | C_LOCAL | - | - |
| Upslope Curvature | grid, output | C_UP | - | - |
| Local Upslope Curvature | grid, output | C_UP_LOCAL | - | - |
| Downslope Curvature | grid, output | C_DOWN | - | - |
| Local Downslope Curvature | grid, output | C_DOWN_LOCAL | - | - |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Upslope Weighting | floating point number | WEIGHTING | - | Minimum: 0.000000
Maximum: 1.000000
Default: 0.500000 |
Command Line
Usage: saga_cmd ta_morphometry 26 [-DEM ] [-C_LOCAL ] [-C_UP ] [-C_UP_LOCAL ] [-C_DOWN ] [-C_DOWN_LOCAL ] [-WEIGHTING ]
-DEM: Elevation
grid, input
-C_LOCAL: Local Curvature
grid, output
-C_UP: Upslope Curvature
grid, output
-C_UP_LOCAL: Local Upslope Curvature
grid, output
-C_DOWN: Downslope Curvature
grid, output
-C_DOWN_LOCAL: Local Downslope Curvature
grid, output
-WEIGHTING: Upslope Weighting
floating point number
Minimum: 0.000000
Maximum: 1.000000
Default: 0.500000