# weightr: Weights of donor catchments In transfR: Transfer of Hydrograph from Gauged to Ungauged Catchments

 weightr R Documentation

## Weights of donor catchments

### Description

Estimate the weighting applied at each time step and to each gauged catchment (donors) for the calculation of the average net rainfall of an ungauged catchment

### Usage

weightr(Rn, distances, ndonors = 5, donors, power = 1, flexible_donor = TRUE)


### Arguments

 Rn net rainfall matrix of donor catchments (rows for time index, and columns for donors index) distances vector of the distances to each donor catchment (see hdist) ndonors maximum number of donor catchments to use donors vector of catchments id from which donors are selected. If empty, the ndonors closest catchments are used power exponent applied in the inverse distance weighting function (see details) flexible_donor boolean indicating if the donor catchments can change during the simulation period according to the availability of discharge observations (see details)

### Details

This function returns a matrix of weights for each time steps (rows) and each gauged catchments (columns) for the calculation of the average net rainfall of an ungauged catchment (see mixr). The weights λ are estimated by an inverse distance weighting function \insertCitedeLavenne2016transfR:

λ_i=\frac{1}{d_i^p}

Σ_{i=1}^{ndonors}λ_i=1

where d is the distances argument and p is the power argument. The weights are rescaled so the sum is equal to 1.

Two strategies to handle missing data in the Rn matrix are possible. If flexible_donor is TRUE, donors catchments are redefined at each time steps, and are chosen among the ones that are effectively gauged at this given time step. This aims to keep a constant number of donor catchments throughout the simulation period. If flexible_donor is FALSE, the donor catchments are chosen once within all the gauged catchments, regardless of missing data and remain the same throughout the entire simulation period. This stability of donor catchments might however leads to a reduced number of donors (below ndonors) during periods of missing data.

### Value

A matrix with the same dimensions as Rn.

### References

\insertRef

deLavenne2016transfR