spm (version 1.2.2)

rfidwpred: Generate spatial predictions using the hybrid method of random forest and inverse distance weighting (RFIDW)

Description

This function is to make spatial predictions using the hybrid method of random forest and inverse distance weighting (RFIDW).

Usage

rfidwpred(
  longlat,
  trainx,
  trainy,
  longlatpredx,
  predx,
  mtry = function(p) max(1, floor(sqrt(p))),
  ntree = 500,
  idp = 2,
  nmax = 12,
  ...
)

Arguments

longlat

a dataframe contains longitude and latitude of point samples (i.e., trainx and trainy).

trainx

a dataframe or matrix contains columns of predictive variables.

trainy

a vector of response, must have length equal to the number of rows in trainx.

longlatpredx

a dataframe contains longitude and latitude of point locations (i.e., the centres of grids) to be predicted.

predx

a dataframe or matrix contains columns of predictive variables for the grids to be predicted.

mtry

a function of number of remaining predictor variables to use as the mtry parameter in the randomForest call.

ntree

number of trees to grow. This should not be set to too small a number, to ensure that every input row gets predicted at least a few times. By default, 500 is used.

idp

numeric; specify the inverse distance weighting power.

nmax

for local predicting: the number of nearest observations that should be used for a prediction or simulation, where nearest is defined in terms of the space of the spatial locations. By default, 12 observations are used.

...

other arguments passed on to randomForest or gstat.

Value

A dataframe of longitude, latitude and predictions.

References

Liaw, A. and M. Wiener (2002). Classification and Regression by randomForest. R News 2(3), 18-22.

Examples

# NOT RUN {
data(petrel)
data(petrel.grid)
rfidwpred1 <- rfidwpred(petrel[, c(1,2)], petrel[, c(1,2, 6:9)], petrel[, 3],
petrel.grid[, c(1,2)], petrel.grid, ntree = 500, idp = 2, nmax = 12)
names(rfidwpred1)
# }
# NOT RUN {
# }