arc.pa.from.nodes {streamDAG}

Obtain arc stream activity outcomes based on bounding nodes

Description

Given nodal water presence absence data \in \{0,1\} for a graph, G, the function calculates arc water presence probabilities using particular rules (see approaches in Details).

Usage

arc.pa.from.nodes(G, node.pa, approach = "aho", na.rm = TRUE)

Arguments

G

Graph object of class igraph. See graph_from_literal.

node.pa

A data frame or matrix of nodal presence absence data with column names corresponding to node names in G.

approach

One of "aho", "dstream", or "ustream" (see Details).

na.rm

For approach = "aho", one of TRUE or FALSE indicating whether NA values should be stripped before calculating means. Ignored for other appraches.

Details

The approach argument currently supports three alternatives "aho", "dstream" and "ustream". Let x_{k} represent the kth arc with bounding nodes u and v.

Under approach = "aho" there are three possibilities: x_{k} = 1.0 if both u and v are wet, x_{k} = 0 if both u and v are dry, and x_{k} = 0.5 if only one of u or v is wet.

Under approach = "dstream", x_{k} = 1.0 if v is wet, and x_{k} = 0 if v is dry.

Conversely, if approach = "ustream", x_{k} = 1.0 if u is wet, and x_{k} = 0 if u is dry.

Value

Returns a matrix whose entries are estimated probabilities of success (e.g. surface water presence) based on the rules given in Aho et al. (2023). Matrix columns specify arcs and rows typically represent time series observations.

Author(s)

Ken Aho

References

Aho, K., Derryberry, D., Godsey, S. E., Ramos, R., Warix, S., Zipper, S. (2023) The communication distance of non-perennial streams. EarthArXiv https://eartharxiv.org/repository/view/4907/

Examples

murphy_spring <- graph_from_literal(IN_N --+ M1984 --+ M1909, IN_S --+ M1993,  
M1993 --+ M1951 --+ M1909 --+ M1799 --+ M1719 --+ M1653 --+ M1572 --+ M1452, 
M1452 --+ M1377 --+ M1254 --+ M1166 --+ M1121 --+ M1036 --+ M918 --+ M823, 
M823 --+ M759 --+ M716 --+ M624 --+ M523 --+ M454 --+ M380 --+ M233 --+ M153, 
M153 --+ M91 --+ OUT)

data(mur_node_pres_abs)
pa <- mur_node_pres_abs[400:405,][,-1]
arc.pa.from.nodes(murphy_spring, pa)
arc.pa.from.nodes(murphy_spring, pa, "dstream")