.help msisqgrl Dec98 "Image Interpolation Package"
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NAME
msisqgrl -- integrate the interpolant over a rectangular region 
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SYNOPSIS
y = msisqgrl (msi, x1, x2, y1, y2)

.nf
    pointer	msi		#I interpolant descriptor
    real	x1		#I lower x limit, 1 <= x1 <= nxpix
    real	x2		#I upper x limit, 1 <= x2 <= nxpix
    real	y1		#I lower y limit, 1 <= y1 <= nypix
    real	y2		#I upper y limit, 1 <= y2 <= nypix
.fi
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ARGUMENTS
.ls msi    
Pointer to the sequential interpolant descriptor structure.
.le
.ls x1, x2
The x limits of integration
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.ls y1, y2
The y limits of integration.
.le
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DESCRIPTION
MSISQGRL integrates the interpolant exactly for rectangular domains
of integration, including partial pixel regions.
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NOTES
Checking for out of bound integration regimes is the responsibility of
the user. MSIFIT must be called before using MSISQGRL.
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SEE ALSO
msigrl
.endhelp