GNU R interpolation methods
Bivariate data interpolation on regular and irregular
grids, either linear or using splines are the main part of this
package. It is intended to provide FOSS replacement functions for
the ACM licensed akima::interp and tripack::tri.mesh functions.
Currently the piecewise linear interpolation part of akima::interp
(and also akima::interpp) is implemented in interp::interp, this
corresponds to the call akima::interp(..., linear=TRUE) which is the
default setting and covers most of akima::interp use cases in
depending packages. A re-implementation of Akimas spline
interpolation (akima::interp(..., linear=FALSE)) is currently under
development and will complete this package in a later
version. Estimators for partial derivatives are already available,
these are a prerequisite for the spline interpolation. The basic
part is currently a GPLed triangulation algorithm (sweep hull
algorithm by David Sinclair) providing the starting point for the
piecewise linear interpolator. As side effect this algorithm is also
used to provide replacements for the basic functions of the tripack
package which also suffer from the ACM restrictions. All functions
are designed to be backward compatible with their akima / tripack
counterparts.
