earthkit.hydro.streamorder¶

Subpackages¶

earthkit.hydro.streamorder.array

Module contents¶

earthkit.hydro.streamorder.shreve(river_network, return_type=None, input_core_dims=None)[source]¶

Computes the Shreve stream order for each node in the river network.

For each node in the river network, this algorithm identifies the upstream nodes and uses them to calculate the Shreve order of the current node.

The Shreve order is defined as:

\begin{align*} s_i &= 1 ~\text{for sources}\\ s_i &= \sum_{k \in \mathrm{Up}(i)} s_k \end{align*}

where:

$\mathrm{Up}(j)$ is the set of upstream nodes flowing into node $j$,
$s_i$ is the Shreve order at node $i$.

Accumulation proceeds in topological order from the sources to the sinks.

Parameters:

river_network (RiverNetwork) – A river network object.
return_type (str, optional) – Either “masked”, “gridded” or None. If None (default), uses river_network.return_type.
input_core_dims (sequence of sequence, optional) – List of core dimensions on each input xarray argument that should not be broadcast. Default is None, which attempts to autodetect input_core_dims from the xarray inputs. Ignored if no xarray inputs passed.

Returns:

Array of Shreve stream order values for every river network node or gridcell, depending on return_type.

Return type:

xarray object

earthkit.hydro.streamorder.strahler(river_network, return_type=None, input_core_dims=None)[source]¶

Computes the Strahler stream order for each node in the river network.

For each node in the river network, this algorithm identifies the upstream nodes and uses them to calculate the Strahler number of the current node.

The Strahler number is defined as:

\begin{align*} u_i &= \max_{k \in \mathrm{Up}(i)} s_k \\ n_i &= \left|\{k \in \mathrm{Up}(i) | s_k = u_i\}\right| \\ s_i &= \begin{cases} 1 & \text{if } n_i = 0 \\ u_i & \text{if } n_i = 1 \\ u_i + 1 & \text{if } n_i \geq 2 \end{cases} \end{align*}