Plan Curvature

This tool calculates the plan curvature (i.e. contour curvature), or the rate of change in aspect along a contour line, from a digital elevation model ($dem$). Curvature is the second derivative of the topographic surface defined by a DEM. Plan curvature characterizes the degree of flow convergence or divergence within the landscape (Gallant and Wilson, 2000).

Usage

wbw_plan_curvature(dem, log_transform = FALSE, z_factor = 1)

Arguments

dem: Raster object of class WhiteboxRaster. See wbw_read_raster() for more details.
log_transform: logical, default FALSE. Wheter log-transform the output raster or not. See details.
z_factor: double, Z conversion factor is only important when the vertical and horizontal units are not the same in the DEM. When this is the case, the algorithm will multiply each elevation in the DEM by the Z conversion factor

Value

WhiteboxRaster object.

Details

WhiteboxTools reports curvature in degrees multiplied by 100 for easier interpretation. The Z conversion factor ($z_factor$) is only important when the vertical and horizontal units are not the same in the DEM. When this is the case, the algorithm will multiply each elevation in the DEM by the Z Conversion Factor.

If the DEM is in the geographic coordinate system (latitude and longitude), the following equation is used:

$$zfactor = \frac{1.0}{111320.0 \times \cos(midlat)}$$

The algorithm uses the same formula for the calculation of plan curvature as Gallant and Wilson (2000). Plan curvature is negative for diverging flow along ridges and positive for convergent areas, e.g. along valley bottoms.

References

For more information, see https://www.whiteboxgeo.com/manual/wbw-user-manual/book/tool_help.html#plan_curvature

Gallant, J. C., and J. P. Wilson, 2000, Primary topographic attributes, in Terrain Analysis: Principles and Applications, edited by J. P. Wilson and J. C. Gallant pp. 51-86, John Wiley, Hoboken, N.J.

Examples