@BeginModule
@NewPage
@Name      = Remapbil
@Title     = Bilinear interpolation
@Section   = Interpolation
@Class     = Interpolation
@Arguments = ifile ofile
@Operators = remapbil genbil

@BeginDescription
This module contains operators for a bilinear remapping of fields between grids in spherical coordinates.
The interpolation is based on an adapted SCRIP library version. 
For a detailed description of the interpolation method see @cite{SCRIP}.
This interpolation method only works on quadrilateral curvilinear source grids.
@EndDescription
@EndModule


@BeginOperator_remapbil
@Name      = remapbil
@Title     = Bilinear interpolation
@Parameter = grid

@BeginDescription
Performs a bilinear interpolation on all input fields.
@EndDescription
@EndOperator


@BeginOperator_genbil
@Name      = genbil
@Title     = Generate bilinear interpolation weights
@Parameter = grid

@BeginDescription
Generates bilinear interpolation weights for the first input field and writes the
result to a file. The format of this file is netCDF following the SCRIP convention.
Use the operator @mod{remap} to apply this remapping weights to a data file with the same source grid.
@EndDescription
@EndOperator


@BeginParameter
@Item = grid
STRING  Target grid description file or name
@EndParameter


@BeginEnvironment
@Item = REMAP_EXTRAPOLATE
This variable is used to switch the extrapolation feature 'on' or 'off'.
By default the extrapolation is enabled for circular grids.
@EndEnvironment


@BeginExample
Say @file{ifile} contains fields on a quadrilateral curvilinear grid.
To remap all fields bilinear to a Gaussian N32 grid, type:
@BeginVerbatim
   cdo remapbil,n32 ifile ofile
@EndVerbatim
@EndExample
