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.help msivector Dec98 "Image Interpolation Package"
.ih
NAME
msivector -- evaluate the interpolant at an array of x and y points
.ih
SYNOPSIS
msivector (msi, x, y, zfit, npts)
.nf
pointer msi #I interpolant descriptor
real x[npts/4*npts] #I x values, 1 <= x <= nxpix
real y[npts/4*npts] #I y values, 1 <= y <= nypix
real zfit[npts] #O interpolated values
int npts #I number of points
.fi
.ih
ARGUMENTS
.ls msi
The pointer to the sequential interpolant descriptor
.le
.ls x, y
The array of x and y values at or in the case tof the drizzle interpolant the
array of quadrilaterals over which to evaluate the interpolant.
.le
.ls zfit
The interpolated values.
.le
.ls npts
The number of points.
.le
.ih
DESCRIPTION
The polynomial coefficients are calculated directly from the data points,
The polynomial interpolants are evaluated using Everett's central difference
formula. The spline interpolant uses the B-spline coefficients
calculated using the MSIFIT routine. The boundary extension algorithm is
projection.
The sinc interpolant is evaluated using a array of data points around
the point in question. The look-up table since is computed by convolving
the data with a pre-computed look-up table entry. The boundary extension
algorithm is nearest neighbor.
The drizzle interpolant is evaluated by summing the data over the
list of user supplied quadrilaterals.
.ih
NOTES
Checking for out of bounds and INDEF valued pixels is the responsibility
of the user. MSIINIT or MSISINIT and MSIFIT must be called before using
MSIVECTOR.
.ih
SEE ALSO
msieval, mrieval
.endhelp
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