fields {fields} | R Documentation |
Fields is a collection of programs for curve and function fitting with an emphasis on spatial data and spatial statistics. The major methods implemented include cubic and thin plate splines, universal Kriging and Kriging for large data sets. One main feature is any covariance function implemented in R can be used for spatial prediction.
Some major methods include:
Tps
Thin Plate spline regression (including GCV)
Krig
Spatial process estimation (Kriging)
krig.image
Spatial process estimate for large problems
The Kriging functions allow you to supply a covariance function that is
written in native S/R code. The Matern family (Matern.cov
) is
included as a built in
covariance.
Some other noteworthy functions are
cover.design
Space-filling designs where the distance
function is expresed in R/S code
as.image
image.plot
image.count
smooth.image
convenient functions
for working with image data
sreg
, qsreg
splint
Fast 1-D smoothing
splines and 1-D
quantile/robust and interpolating cubic splines
There are also generic functions that support these methods such as
plot
- diagnostic plots of fit
summary
- statistical summary of fit
print
- shorter version of summary
surface
- graphical display of fitted surface
predict
- evaluation fit at arbitrary points
predict.se
- prediction standard errors at arbitrary points.
sim.rf
- Simulate a random fields on a 2-d grid.
To get started, try some of the examples from help files for Tps
or
Krig
. See also the manual/tutorial at
http://www.cgd.ucar.edu/stats/Software/fields
DISCLAIMER:
This is software for statistical research and not for commercial uses. The authors do not guarantee the correctness of any function or program in this package. Any changes to the software should not be made without the authors permission.
set.panel() fit<- Tps(ozone$x, ozone$y) # fits a thin plate spline surface to ozone # measurements. summary(fit) #summary of the fit plot(fit) # diagnostic plots of fit and residuals. surface( fit, type="I") # image and contour plot of the fitted surface