	(REGULAR VERB)

	PDOC is used as part of a PROCEDURE to reduce a five-point
	scan or sequence of scans.  The results are displayed on the
	graphics screen and written to a log file.

	PDOC works only for data taken with the 12-meter telescope.

        The raw five-point scan or scans need to be processed into a
	"synthetic scan" before PDOC can be used.  The preprocessing
	needed depends on the type of observation, spectral line or
	continuum.  This preprocessing is generally done in a PROCEDURE.
	In all cases, the header information of the "synthetic scan"
	should be from the Center pointing position.  The five positions
	should correspond to North, South, Center, East and West.

	The magnitude of the offset from the Center should be the same
	for all 4 offset positions.  When the fitted positions are
	converted to offsets, the value of the BFWHM header word is
	assumed to correspond to the magnitude of each offset.
	Note that currently, the 12-meter data header generally contains
	half of the full width at half maximum at this location (i.e.
	half the value suggested by the name of the header word).

	No adverbs are set or used by PDOC

	The environment variable POPSPOINTDAT should contain the name of
	the PDOC log file.  If POPSPOINTDAT is not set, point.dat in the
	current directory is assumed.

	The procedure names indicated below may change.  Be sure to
	check with the 12-meter staff for up-to-date names and locations
	of 12-meter procedures.

C------------------------- Continuum -----------------------------------
C-
C-	PDOC expects 10 values in the data array.  The first 5 data
C-	values should correspond to the average values at each of the 5
C-	positions in the five-point scan.  They must appear in the
C-	following order: North, South, Center, East, West.  The other 5
C-	data values should be the associated rms's in the same order.
C-
C-	PDOC fits 2 Gaussians using the 3 points along each coordinate
C-	axis.  The first fit on each axis solves for the center, height
C-	and width.  The second fit forces the Gaussian to have a full
C-	width at half maximum equal to twice the BFWHM indicated in the
C-	header (see the note above on the current use of BFWHM at the
C-	12-meter).  Normally, the fitted FWHM will be close to the
C-	assumed FWHM.
C-
C-	The rms's are NOT currently used by PDOC.  They should be.
C-
C-	The procedure FIVE, which is available at the 12-meter, is used
C-	to reduce standard continuum five-point scans.
C-
C-	EXAMPLE:
C-
C-	You wish to reduce the five-point scan 1234 to determine new
C-	total pointing corrections.
C-
C-	>FIVE(1234)
C-
C-	The graphics screen should display the results of PDOC.  The new
C-	total pointing corrections which you should give to the operator
C-	are indicated under the "CORRECTED OFFSET" field.  These offsets
C-	correspond to the "FIT WITH NO RESTRICTIONS" result.  The units
C-	are SMM:SS, where MM is arcminutes and SS is arcseconds and
C-	S is + or -.
C-
C-	Other information found on the PDOC graphics screen includes:
C-	basic scan information at the top, the commanded telescope
C-	position and current pointing corrections, the subreflector
C-	beam thrown, the data values and rms's at each position,
C-	the fitted offsets (from the current position), peaks, and
C-	FWHM beam widths.  In addition, two symbols are drawn indicating
C-	the approximate best fit location of the pointing source from
C-	each fit: "N" indicates the "FIT WITH NO RESTRICTIONS and "F"
C-	indicates the "FIT WITH AZBW=ELBW=".
C-
C-----------------------------------------------------------------------
L------------------------- Spectral Line -------------------------------
L-
L-	PDOC expects 10 values in the data array.  These should be 2
L-	sets of 5 values with each set corresponding to North, South,
L-	Center, East and West pointing positions, in that order.
L-	Generally the first 5 values should correspond to integrated
L-	intensities and the second set should correspond to peak
L-	intensities although PDOC ultimately has no way to tell this and
L-	will provide a fit to each set of five values.
L-
L-	For each set of 5 values, PDOC fits 2 Gaussian using the 3
L-	points along each coordinate axis (for a total of 8 Gaussians).
L-	The first fit on each axis solves for the center, height, and
L-	width.  The second fit forces the Gaussian to have a full width
L-	at half maximum equal to twice the BFWHM indicated in the header
L-	(see the note above on the current use of BFWHM at the
L-	12-meter). Normally, the fitted FWHM will be close to the
L-	assumed FWHM.
L-
L-	The procedure LF (for Line FIVE), which is available at the
L-	12-meter, is used to reduce a standard five point spectral line
L-	map.
L-
L-	EXAMPLE:
L-
L-	You wish to reduce a five-point spectral line map where the scan
L-	1234 is the scan number of the Center position to determine new
L-	total pointing corrections.
L-
L-	>LF(1234)
L-
L-	(various questions will be asked concerning baseline and
L-	integration regions.)
L-
L-	The graphics screen will eventually display the results of PDOC.
L-	The new total pointing corrections which you should give the
L-	operator are indicated after "CORRECTED MAIN OFFSETS".
L-	These offsets correspond to the "NONRESTRICTED FIT" (i.e. the
L-	fit where the width is allowed to vary).  The fit for each
L-	set of 5 data values is indicated as well as the average of
L-	these two fits.  The units are SMM:SS, where MM is arcminutes
L-	and SS is arcseconds and S is + or -.
L-
L-	Other information found on the PDOC graphics screen includes:
L-	basic scan information at the top, the commanded telescope
L-	position and current pointing corrections, the data values
L-	at each position (value from first set of 5 appears above
L-	value from second set), the fitted offsets (from the current
L-	position), peaks, and FWHM beam widths.  In addition, 4 symbols
L-	are drawn indicating the approximate best fit location of the
L-	pointing source from each fit (relative to the current pointing
L-	offsets, the symbol for each fit is shown above the value for
L-	that fit (A, B, C, and D).
L-
L-----------------------------------------------------------------------
