mixr: Transfer of net rainfall and discharge simulation
In transfR: Transfer of Hydrograph from Gauged to Ungauged Catchments

Description Usage Arguments Details Value See Also Examples

Combine net rainfall of gauged catchments to simulate the discharge of an ungauged catchment.

mixr(
  obs,
  sim,
  mdist,
  distance = "rghosh",
  gres = 5,
  weightO = 0.8,
  weightC = 0.2,
  parallel = FALSE,
  cores = NULL,
  power = 1,
  ndonors = 5,
  donors = NULL,
  maxdist = 50000,
  flexible_donor = TRUE,
  cv = FALSE,
  save_donor = FALSE,
  verbose = TRUE
)

`obs`	"transfR" object of the gauged catchments
`sim`	"transfR" object of the ungauged catchments
`mdist`	the distance matrix between gauged and ungauged catchments as computed by the function hdist
`distance`	the method to use for computing distance matrix if `mdist` is not provided. Possible values are "ghosh", "ghosh2", "rghosh", "points", "centroids", "combined" as available in the function hdist
`gres`	resolution of spatial discretisation (number of points by km²) for Ghosh distance (see the function hdist)
`weightO`	weight given to the distance between outlets if `distance` is "combined" (see the function hdist)
`weightC`	weight given to the distance between centroids if `distance` is "combined" (see the function hdist)
`parallel`	logical indicating if the computation should be parallelised
`cores`	the number of cores to use for parallel execution if `parallel` is TRUE. If not specified, the number of cores is set to the value of `parallel::detectCores()`
`power`	exponent applied in the inverse distance weighting strategy as defined by the function weightr
`ndonors`	maximum number of catchments to be used to simulate discharge of an ungauged catchment as defined by the function weightr
`donors`	vector of catchments id from which donors are selected. If empty, the `ndonors` closest catchments are used
`maxdist`	maximum distance between a gauged and an ungauged catchment to allow the net rainfall to be transfered. This threshold is applied on the `mdist` distance matrix. If no units is provided, `maxdist` is assumed to be in [m].
`flexible_donor`	boolean indicating if the donor catchments can change during the simulation period according to the availability of discharge observations. See weightr for more details
`cv`	boolean indicating if cross validation evaluation should be done. If true, it will estimate the net rainfall of every gauged catchments (`obs`) as if they were ungauged (leave-one-out evaluation)
`save_donor`	boolean indicating if the net rainfall of each of the `ndonors` catchments should be stored in the sim object for further analysis. If true, it is adding three new space-time attributes in the `sim` object called "RnDonor", "Idonor" and "Wdonor" describing the net rainfall, the id and the weight of the donor catchments respectively
`verbose`	boolean indicating if information messages should be written to the console

This function is a wrapper function for hdist and weightr to directly estimate the net rainfall on a set of ungauged catchments (sim) from a set of gauged catchments (obs). It returns the simulated net rainfall as a new space-time attribute in the sim object called "RnSim". The simulated net rainfall of a given ungauged catchment i is a weighted average of the net rainfalls of ndonors gauged catchments j:

R_n^i =Σ_{j=1}^{ndonors} R_n^j \cdot λ_j

where λ_j are defined by a inverse distance weighting function (see weightr).

The sim object incremented by the new computed attributes.

hdist, weightr

data(Oudon)
object <- as_transfr(st=Oudon$obs,hl=Oudon$hl)
object <- velocity(object)
object <- uh(object)
object <- lagtime(object)
object <- rapriori(object)
object <- inversion(object, parallel = TRUE, cores=2)
mdist  <- hdist(x=object, y=object, method="rghosh")
object <- mixr(obs = object, mdist=mdist, parallel = TRUE, cores=2,
cv=TRUE, flexible_donor=TRUE, save_donor = FALSE)
object <- convolution(object, save_donor = FALSE)
plot(object,i=1,attribute=c("Qobs","Qsim"))