pyflwdir.FlwdirRaster.snap#

FlwdirRaster.snap(idxs=None, xy=None, mask=None, max_length=None, unit='cell', direction='down')[source]#

Returns the last index in down- or upstream direction from the starting points where:

  1. a pit is found (including) or now more upstream cells are found; or

  2. a True cell is found in mask (including)

  3. the max_length threshold is exceeded.

To define starting points, either idxs or xy should be provided.

Parameters:

  • idxs (array_like, optional) – linear indices of starting point, by default is None.

  • xy (tuple of array_like of float, optional) – x, y coordinates of starting point, by default is None.

  • mask (2D array of bool) – True at cell where to snap to

  • max_length (float, optional) – maximum length of trace

  • unit ({'m', 'cell'}, optional) – unit of length, by default ‘cell’

  • direction ({'up', 'down'}, optional) – direction of path, be default ‘down’, i.e. downstream

Returns:

  • array_like of int – linear index of snapped cell

  • array_like of float – distance along path between start and snap cell.