Description
Fields is for curve, surface and function fitting with an
emphasis on splines, spatial data and spatial statistics. The
major methods include cubic, and thin plate splines, Kriging
and compact covariances for large data sets. The splines and
Kriging methods are supporting by functions that can determine
the smoothing parameter (nugget and sill variance) by cross
validation and also by restricted maximum likelihood. A major
feature is that any covariance function implemented in R with
the (simple) fields format can be used for spatial prediction.
Some tailored optimization functions are supplied for finding
the MLEs for the Matern family of covariances. There are also
many useful functions for plotting and working with spatial
data as images. This package also contains an implementation of
sparse matrix methods for large data sets and currently
requires the sparse matrix (spam) package for testing and use
with large data sets. But spam is not required for the
standard spatial functions. Use help(fields) to get started and
for an overview. The fields source code is heavily commented
and provides useful explanations of numerical details in
addition to the manual pages.