interp2pnt: Bilinear and Bicubic Interpolation to Points
In jjvanderwal/climates: Methods for working with weather & climate

Description Usage Arguments Value Author(s) See Also Examples

This code was includes bicubic interpolation and bilinear interpolation adapted from Numerical Recipes in C: The are of scientific computing http://www.nrbook.com/nr3/ (chapter 3... bicubic interpolation) and a bicubic interpolation from http://www.paulinternet.nl/?page=bicubic in java code.

Inputs are a list of points to interpolate to from raster objects of class 'asc' (adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package).

1	interp2pnt(mat, xout, yout, xin = NULL, yin = NULL, type = 2)

`mat`	a matrix of data that can be a raster matrix of class 'asc' (adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package) NA values are not permitted.. data must be complete.
`xout`	a vector of data representing x coordinates of the output grid. Resulting grid must have square cell sizes if mat is of class 'asc', 'RasterLayer' or 'SpatialGridDataFrame'.
`yout`	a vector of data representing x coordinates of the output grid. Resulting grid must have square cell sizes if mat is of class 'asc', 'RasterLayer' or 'SpatialGridDataFrame'.
`xin`	a vector identifying the locations of the columns of the input data matrix. These are automatically populated if mat is of class 'asc', 'RasterLayer' or 'SpatialGridDataFrame'.
`yin`	a vector identifying the locations of the rows of the input data matrix. These are automatically populated if mat is of class 'asc', 'RasterLayer' or 'SpatialGridDataFrame'.
`type`	an integer value representing the type of interpolation method used. 1 - bilinear adapted from Numerical Recipes in C 2 - bicubic adapted from Numerical Recipes in C 3 - bicubic adapted from online java code

A vector of values in the same order and length of the inputs xout and yout.

Jeremy VanDerWal jjvanderwal@gmail.com

interp2grid

## Not run: 

#create some data
tx = seq(0,3,0.1)
ty = seq(0,3,0.1)
txy = data.frame(x=tx,y=ty)

#create a matrix
tmat = matrix(runif(16,1,16),nr=4)

#do the interpolations
txy$bilinear1 = interp2pnt(tmat,tx,ty,type=1)
txy$bicubic2 = interp2pnt(tmat,tx,ty,type=2)
txy$bicubic3 = interp2pnt(tmat,tx,ty,type=3)

#look at the data
head(txy)

## End(Not run)