Creates an indicator grid (1, 0) of upward curved grid cells according to the Peuker and Douglas algorithm.
With this tool, the DEM is first smoothed by a kernel with weights at the center, sides, and diagonals. The Peuker and Douglas (1975) method (also explained in Band, 1986), is then used to identify upwardly curving grid cells. This technique flags the entire grid, then examines in a single pass each quadrant of 4 grid cells, and unflags the highest. The remaining flagged cells are deemed “upwardly curved”, and when viewed, resemble a channel network. This proto-channel network generally lacks connectivity and requires thinning, issues that were discussed in detail by Band (1986).
The center weight parameter used by a kernel to smooth the DEM before the tool identifies upwardly curved grid cells.
Default: 0.4
The side weight parameter used by a kernel to smooth the DEM before the tool identifies upwardly curved grid cells.
Default: 0.1
The diagonal weight parameter used by a kernel to smooth the DEM before the tool identifies upwardly curved grid cells.
Default: 0.05
processing.runalg('taudem:peukerdouglas', elevation_grid, center_weight, side_weight, diagonal_weight, stream_source_grid)