rfidwpred function

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

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

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.

Returns

A dataframe of longitude, latitude and predictions.

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)
## End(Not run)

References

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

Author(s)

Jin Li