sbf {SpherWave}R Documentation

Extrapolation with Multi-sale SBF's

Description

This function performs extrapolation with multi-sale SBF's.

Usage

sbf(obs, latlon, netlab, eta, method, approx=FALSE,
    grid.size=c(50, 100), lambda=NULL, p0=0, latlim=NULL, 
    lonlim=NULL) 

Arguments

obs observations
latlon grid points of observation sites in degree. Latitude is the angular distance in degrees of a point north or south of the Equator. North/South are represented by +/- sign. Longitude is the angular distance in degrees of a point east or west of the Prime (Greenwich) Meridian. East/West are represented by +/- sign.
netlab vector of labels representing sub-networks
eta bandwidth parameters for Poisson kernel
method extrapolation methods, `"ls"' or `"pls"'
approx if TRUE, approximation is used.
grid.size grid size (latitude, longitude) of extrapolation site
lambda smoothing parameter for penalized least squares method
p0 specifies starting level for extrapolation. Among resolution levels 1, ..., L, resolution levels p0+1, ..., L will be included for extrapolation.
latlim range of latitudes in degree
lonlim range of longitudes in degree

Details

This function performs extrapolation with multi-sale SBF's.

Value

An object of class `sbf'. This object is a list with the following components.

obs observations
latlon grid points of observation sites in degree
netlab vector of labels representing sub-networks
eta bandwidth parameters for Poisson kernel
method extrapolation methods, `"ls"' or `"pls"'
approx if TRUE, approximation is used.
grid.size grid size (latitude, longitude) of extrapolation site
lambda smoothing parameter for penalized least squares method
p0 starting level for extrapolation. Resolution levels p0+1, ..., L is used for extrapolation.
gridlon longitudes of extrapolation sites in degree
gridlat latitudes of extrapolation sites in degree
nlevels the number of multi-resolution levels
coeff interpolation coefficients
field extrapolation on grid.size
density density on observation's locations
latlim range of latitudes in degree
lonlim range of longitudes in degree

References

Oh, H-S. (1999) Spherical wavelets and their statistical analysis with applications to meteorological data. Ph.D. Thesis, Department of Statistics, Texas A&M University, College Station.

Li, T-H. (1999) Multiscale representation and analysis of spherical data by spherical wavelets. SIAM Journal on Scientific Computing, 21, 924–953.

Oh, H-S. and Li, T-H. (2004) Estimation of global temperature fields from scattered observations by a spherical-wavelet-based spatially adaptive method. Journal of the Royal Statistical Society Ser. B, 66, 221–238.

See Also

swd, swthresh, swr.

Examples

### Observations of year 1967
#data(temperature)
#names(temperature)

# Temperatures on 939 weather stations of year 1967    
#temp67 <- temperature$obs[temperature$year == 1967] 
# Locations of 939 weather stations    
#latlon <- temperature$latlon[temperature$year == 1967, ]

### Network design by BUD
#data(netlab)

### Bandwidth for Poisson kernel
#eta <- c(0.961, 0.923, 0.852, 0.723, 0.506)

### SBF representation of the observations by pls
#out.pls <- sbf(obs=temp67, latlon=latlon, netlab=netlab, eta=eta, 
#    method="pls", grid.size=c(50, 100), lambda=0.89)

[Package SpherWave version 1.1.0 Index]