topotoolbox.FlowObject

topotoolbox.FlowObject#

class topotoolbox.FlowObject(grid: GridObject, bc: ndarray | GridObject | None = None, hybrid: bool = True)[source]#

Bases: object

A class containing containing (water-) flow information about a given digital elevation model (DEM).

__init__(grid: GridObject, bc: ndarray | GridObject | None = None, hybrid: bool = True)[source]#

The constructor for the FlowObject. Takes a GridObject as input, computes flow direction information and saves them as an FlowObject.

Parameters:

  • grid (GridObject) – The GridObject that will be the basis of the computation.

  • bc (ndarray or GridObject, optional) – Boundary conditions for sink filling. bc should be an array of np.uint8 that matches the shape of the DEM. Values of 1 indicate pixels that should be fixed to their values in the original DEM and values of 0 indicate pixels that should be filled.

  • hybrid (bool, optional) – Should hybrid reconstruction algorithm be used to fill sinks? Defaults to True. Hybrid reconstruction is faster but requires additional memory be allocated for a queue.

Notes

Large intermediate arrays are created during the initialization process, which could lead to issues when using very large DEMs.

Methods

__init__(grid[, bc, hybrid])

The constructor for the FlowObject.

flow_accumulation([weights])

Computes the flow accumulation for a given flow network using optional weights.
flow_accumulation(weights: ndarray | float = 1.0)[source]#

Computes the flow accumulation for a given flow network using optional weights. The flow accumulation represents the amount of flow each cell receives from its upstream neighbors.

Parameters:

weights (np.ndarray | float, optional) – An array of the same shape as the flow grid representing weights for each cell, or a constant float value used as the weight for all cells. If weights=1.0 (default), the flow accumulation is unweighted. If an ndarray is provided, it must match the shape of the flow grid., by default 1.0

Returns:

A new GridObject containing the flow accumulation grid.

Return type:

GridObject

Raises:

ValueError – If the shape of the weights array does not match the shape of the flow network grid.