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  <td><br><h2>proc bars</h2></td>
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  <small>
  <a href="../doc/Welcome.html"><img src="../doc/ploticus.gif" border=0></a><br>
  <a href="../doc/Welcome.html">Welcome</a> &nbsp; &nbsp;
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.>>

.TH proc_bars PL "12-SEP-2001   PL www.sgpr.net"
 
.ig >>
<center>
<img src="../gallery/bars0.gif">
</center>
.>>

.SH DESCRIPTION
\fBproc bars\fR uses data to draw bargraphs, histograms, error bars,
or segment bars, in 
the vertical or horizontal directions.

.SH VERTICAL vs. HORIZONTAL BARS
Bars can be vertical or horizontal.  
This is controlled by the \fChorizontalbars\fR or \fCaxis\fR attributes.
For the purposes of the descriptions herein, we will 
assume vertical bars.  Everything works essentially
the same way for horizontal bars, except that 
X and Y should be read as reversed in the descriptions.

.SH FEATURES
Stacked bars, clusters of bars, various labeling options, and variable bar width.

.SH EXAMPLES
See the Gallery Bars examples
.ig >>
<a href="../gallery/gall.bars.html"><img src="../gallery/btn/here.gif"></a>
and
<a href="../gallery/gall.hbars.html"><img src="../gallery/btn/here.gif"></a>
.>>

.SH UNPLOTTABLE DATA
Invalid data points are omitted.
If \fCtruncate\fR is set to \fCyes\fR, then
bars extending beyond the plotting area are truncated to the 
limit of the plotting area;
if both the minima and the maxima of a bar segment or error bar
lie outside of the plotting area, the bar is omitted with a warning.

.SH PREREQUISITES
A plotting area must be set up using \fBproc areadef\fR 
and \fBproc getdata\fR must be executed to 
access or define some data.

.SH MODES 
.LP
Bars can be generated from data using one of several modes
(remember to reverse X and Y in these descriptions if doing
horizontal bars):
.LP 
\fBBars "where they fall":\fR  
.IP
By specifying \fClenfield\fR but not \fClocfield\fR, bars 
are graphed at consecutive unit locations in X.
The length of bars is controlled by the plottable values found 
in \fClenfield\fR.
.LP 
\fBBars at specified locations:\fR
.IP
By specifying both \fClenfield\fR and \fClocfield\fR,
bars are produced at the X locations found in \fClocfield\fR
and the length of bars is controlled by the plottable values found 
in \fClenfield\fR.
.LP 
\fBBar segments (to show ranges):\fR
.IP
By specifying \fCsegmentfields\fR, bars will be drawn
as segments between two plottable values, to show ranges.
This mode may be used with or without \fClocfield\fR,
and \fClenfield\fR is not applicable.
.LP 
\fBError bars:\fR
.IP
By specifying \fClenfield\fR and \fCerrbarfields\fR
error bars centered on the Y values in \fClenfield\fR 
are produced.  
This mode may be used with or without \fClocfield\fR.
The length of the error bars is 
controlled by the values in the \fCerrbarfields\fR
(which have presumably been precomputed; use \fBproc rangebar\fR
to caluclate mean/standard deviation and draw bars).
The color & style of the error bar line can be
controlled using the \fCthinbarline\fR attribute.
.LP
\fBStacked and/or clustered bars:\fR
.IP
\fBproc bars\fR draws one set of bars per invocation.
Stacked and clustered bars may be done using multiple invocations.
To do the upper portions of a stacked bargraph, the \fCstackfields\fR
attribute controls what data the bars are to be placed above.
To do clustered bars, the \fCcluster\fR attribute is used.
.LP
\fBVery thin bars / histograms:\fR
.IP
The \fCthinbarline\fR attribute should be used when very thin line bars
are desired and to specify style for error bar lines.

.SH MANDATORY ATTRIBUTE
The \fClenfield\fR attribute MUST be specified.

.SH ATTRIBUTES
.LP
(Remember to reverse X and Y in these descriptions if
horizontal bars are being generated.)

.LP
\fBlenfield\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI dfield \fR
.ig >>
</a>
.>>
.IP
The contents of this data field will be used to control bar length.
These should be plottable values in Y. 
Example: \fClenfield: 2\fR

.LP
\fBlocfield\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI dfield \fR
.ig >>
</a>
.>>
.IP
The contents of this data field will be used to control bar location in X.
These should be plottable values in X.  
If \fClocfield\fR is not specified, bars will be located at consecutive
unit locations in X.
Example: \fClocfield: 1\fR

.LP
\fBhorizontalbars\fR \fCyes\fR | \fCno\fR
.IP
If yes, bars will be horizontal.
Otherwise, bars will be vertical.
Example: \fChorizontalbars: yes\fR

.LP
\fBaxis\fR \fCx\fR | \fCy\fR
.IP
Has the same effect as the \fChorizontalbars\fR attribute.
Specifies the axis that the bar lengths will be plotted against.
Use \fCy\fR to produce vertical bars (the default),
or \fCx\fR to produce horizontal bars.
Example: \fCaxis: x\fR

.LP
\fBcolor\fR 
.ig >>
<a href="color.html">
.>>
\fI color \fR
.ig >>
</a>
.>>
.IP
Color of the bars.  Example: \fCcolor: green\fR
If bars are very thin, or error bars are being done, the
color is specified via the \fCthinbarline\fR attribute.
The \fChatch\fIN\fR color values may be useful when working
in Postscript monochrome.  See also the \fCcolorlist\fR 
and \fCcolorfield\fR attributes.


.LP
\fBlegendlabel\fR  
.ig >>
<a href="attributetypes.html#text">
.>>
\fI text \fR
.ig >>
</a>
.>>
.IP
A label to be associated with the current set of bars in the legend.
\fBproc legend\fR must be executed later in order to 
render the legend.


.LP
\fBoutline\fR 
.ig >>
<a href="linedetails.html">
.>>
\fI linedetails \fR
.ig >>
</a>
.>>
.IP
If \fCyes\fR or a linedetails specification, causes bars to be outlined
with a line.  If \fCno\fR or \fCnone\fR, no outline is produced.
Default is \fCyes\fR, which gives a thin black outline.
.br
Example: \fCoutline: color=blue\fR
.br
Example: \fCoutline: no\fR

.LP
\fBbarwidth\fR \fIn\fR
.IP
Width of bars in 
.ig >>
<a href="attributetypes.html#positionunits">
.>>
absolute units
.ig >>
</a>
.>>
 .  If not specified width will be determined based on scaling,
but this may not always be satisfactory.  For very thin bars
use \fCthinbarline\fR (see below).

.LP
\fBthinbarline\fR
.ig >>
<a href="linedetails.html">
.>>
\fI linedetails \fR
.ig >>
</a>
.>>
 | \fCyes\fR | \fCno\fR
.IP
If specified, bars will be rendered as lines with the given properties.
\fCyes\fR gives a default thin black line.  This should be used when bars are
to be very thin; otherwise, they may not be visible depending on your display
resolution.  This attribute also controls the style, color, etc. of error bars.


.LP
\fBbarsrange\fR \fImin\fR [\fImax\fR]
.IP
If specified, and if \fClocfield\fR is used to position bars,
bars will only appear if the value in \fClocfield\fR is within 
this range.  If only one value is given it is taken as the \fBminima\fR.

.LP
\fBstackfields\fR \fC*\fR 
.br
\fIor\fR
.br
\fBstackfields\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI dfield1 \fR
.ig >>
</a>
.>>
 .. \fIdfieldN\fR
.IP
If specified, causes current set of bars to be placed on top
of earlier sets.  
If \fC*\fR is given, it is taken to mean "stack this set of bars on top of
all previously plotted bars" (same area, same cluster member).
Fields may be specified explicitly (see the examples).
Max number of stackable fields is 40.  \fC*\fR is new in version 1.34.
.br
Example: \fCstackfields: *\fR
.br
Example: \fCstackfields: 3 4 5\fR

.LP
\fBcluster\fR \fIposition\fR \fC/\fR \fInmembers\fR
.IP
If specified, causes the current set of bars to be rendered as a
member of a cluster.  \fIposition\fR indicates which member of the
cluster is being done (1 = leftmost).  \fInmembers\fR
indicates how many bars are in each cluster.
.br
Example: \fCcluster: 1 / 4\fR  would be used to render the
first set of bars where clusters of 4 are being done.
.IP
You can also say \fCcluster: 1 of 4\fR if you prefer.

.LP
\fBclustersep\fR \fIn\fR
.IP
If specified when doing clustered bars, members of each cluster
are separated from each other by \fIn\fR 
.ig >>
<a href="attributetypes.html#positionunits">
.>>
absolute units
.ig >>
</a>
.>>
  Default is 0.0 (bars butted up against one another).

.LP
\fBcrossover\fR 
.ig >>
<a href="attributetypes.html#plotvalue">
.>>
\fI plotvalue \fR
.ig >>
</a>
.>>
.IP
If specified, causes plottable values less than this to be shown
using bars extending in the opposite direction.  
Typically used for values less than zero.  
Default is no crossover.
Example: \fCcrossover: 0\fR

.LP
\fBtruncate\fR \fCyes\fR | \fCno\fR
.IP
If \fCyes\fR, bars and labels will be truncated to the plotting area.
Default is \fCno\fR.

.LP
\fBsegmentfields\fR 
 [ \fIstart-dfield\fR ] 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI stop-dfield \fR
.ig >>
</a>
.>>
.IP
If specified, causes segment bars to be rendered rather than
length-based bars.  These are typically used to display ranges
(but should not be confused with \fBproc rangebar\fR which computes
and displays percentiles).
Each bar will be drawn from the data value in \fIstart-dfield\fR 
to the data value in the \fIstop-dfield\fR.
.br
Example: \fCsegmentfields: 1 3\fR

.LP
\fBerrbarfields\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI errlowfield \fR
.ig >>
</a>
.>>
[ \fIerrhifield\fR ]
.IP
If specified, causes error bars to be rendered rather than
length based bars.  \fClenfield\fR must also be specified.
A thin error bar with tails is drawn from the value in \fClenfield\fR,
downward for the distance located in \fIerrlowfield\fR, and then
upward for the distance located in \fIerrhifield\fR.
If \fIerrhifield\fR is not given, the error bar is assumed to
be symmetrical.
See also \fCerrbarmult\fR.
.br
Example: \fCerrbarfields:  3\fR

.LP
\fBerrbarmult\fR  \fIn\fR
.IP
If specified, error bars will be drawn to \fIn\fR times the distance
given in the data.  Useful for drawing error bars showing 2 x standard error.

.LP
\fBtails\fR \fIn\fR
.IP
If specified, tails of length \fIn\fR (in 
.ig >>
<a href="attributetypes.html#positionunits">
.>>
 absolute units 
.ig >>
</a>
.>>
 ) are 
rendered at the top and bottom of each bar.  Typcially used
with error bars.  Tails of a default length are automatically
rendered if \fCerrbarfields\fR is used.
Example: \fCtails: 0.2\fR

.LP
\fBleftticfield\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fIdfield\fR
.ig >>
</a>
.>>
.LP
\fBmidticfield\fR \fIdfield\fR
.LP
\fBrightticfield\fR \fIdfield\fR
.LP
\fBticlen\fR \fIh\fR
.IP
If specified, a left-pointing, centered, or right-pointing tic mark 
will be displayed at the value in \fIdfield\fR.  The tics are drawn
on top of the bars using the current line (outline or thinbarline), beginning
in the center of the bar.
Length is set by attribute \fCticlen\fR, which sets the tick length
to \fIh\fR
.ig >>
<a href="attributetypes.html#positionunits">
.>>
absolute units
.ig >>
</a>
.>>
 .

.LP
\fBselect\fR  
.ig >>
<a href="condex.html">
.>>
\fI conditional-expression \fR
.ig >>
</a>
.>>
.IP
Allows data rows to be selected for inclusion 
using a selection expression.

.LP
\fBreverseorder\fR  \fCyes\fR | \fCno\fR
.IP
If \fCyes\fR, and bars are being located in consecutive unit locations
(i.e. no \fClocfield\fR specified), bars will be placed in reverse order.

.LP
\fBcolorfield\fR
.ig >>
<a href="attributetypes.html#dfield">
.>>
\0dfield
.ig >>
</a>
.>>
.IP
Allows bars to be rendered in multiple colors, the color being determined by data.
This attribute specifies a field in the data that will control the color
of the bar being drawn.  Beforehand, 
.ig >>
<a href="legendentry.html">
.>>
\0proc legendentry
.ig >>
</a>
.>>
must be invoked to set up one or more legend entries.
A \fCtag\fR must be supplied with each.  These tags correspond to the
contents of the color lookup field.  See this example:
.ig >>
<a href="../gallery/colorfld.htm">
.>>
\0colorfld
.ig >>
</a>
.>>


.LP
\fBcolorlist\fR \fIlist\fR
.IP
Allows bars to be rendered in multiple colors.
It can operate in one of two ways.
.IP
1) if \fIlist\fR is a space-separated
list of 
.ig >>
<a href="color.html">
.>>
\fIcolors\fR
.ig >>
</a>
.>>
then the individual bars will be rendered using these colors.
.br
Example: \fCcolorlist: red yellow blue green\fR
.br
The leftmost bar will be red, the second yellow, and so on.
If there are more bars then given colors,
the remaining bars will be rendered using the default color, e.g.
the value given in the \fCcolor\fR attribute.  
A gallery example where this was done is 
.ig >>
<a href="../gallery/timeline1a.htm">
.>>
timeline1a
.ig >>
</a>
.>>
.IP
2) \fIlist\fR may be some number of pairs having the form 
\fIn\fR 
.ig >>
<a href="color.html">
.>>
\fI color \fR
.ig >>
</a>
.>>
where \fIn\fR is an integer. 
.br
Example: \fCcolorlist: 4 yellow 8 pink\fR
.br
The fourth bar from the left will be yellow; the eighth pink.
All other bars will be rendered using the default color, e.g.
the value given in the \fCcolor\fR attribute.  
A gallery example where this was done is 
.ig >>
<a href="../gallery/hbars1.htm">
.>>
hbars1
.ig >>
</a>
.>>
.IP
Any legend entries for the various colors must be
done explicitly using proc legendentry.
.br
(This attribute is new with version 1.32)

.LP
\fBbarwidthfield\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fIdfield\fR
.ig >>
</a>
.>>
.IP
If specified, bar widths will be controlled by the contents of this field.
These values should be in scaled basic units for the axis that the bars are perpendicular to.

.LP
\fBhidezerobars\fR \fCyes\fR | \fCno\fR
.IP
If \fCyes\fR, bars that are zero-length will not be drawn at all.
Default is \fCno\fR (zero length bars may be visible as a thin line).
New in version 1.40.


.SH BAR LABELING OPTIONS
.LP
One label may be rendered per bar.  It may be a value label
(\fCshowvalues\fR), or label taken from a data field.

.LP
\fBshowvalues\fR \fCyes\fR | \fCno\fR
.IP
If \fCyes\fR, the plottable Y value will be displayed near the
end of each bar.  Default is \fCno\fR.  Text details may be 
controlled using the \fClabeldetails\fR attribute (the \fCadjust\fR
subattribute may be used to control the location of the labels).
Numeric decimal format may be controlled by the \fCnumbersformat\fR
attribute.
Example: \fCshowvalues: yes\fR

.LP
\fBnumbersformat\fR 
.ig >>
<a href="attributetypes.html#printfspec">
.>>
\fI printfspec \fR
.ig >>
</a>
.>>
.IP
Allows control over number decimal format presentation in bar labels.
Default is \fC%g\fR.  (New in 1.36)
.br
Example: \fCnumbersformat: %8.0f\fR

.LP
\fBlabelzerovalue\fR \fCyes\fR | \fCno\fR
.IP
Used with \fCshowvalues\fR.
If \fCyes\fR, zero length bars will have a value label displayed.
Default is \fCno\fR, to not display any value for zero length bars.


.LP
\fBlabeldetails\fR 
.ig >>
<a href="textdetails.html">
.>>
\fI textdetails \fR
.ig >>
</a>
.>>
.IP
Details concerning the appearance of the labelling (both end-of-bar
labels and longways labels).
Example: \fCtextdetails: adjust=0,-0.3  size=6\fR

.LP
\fBlabelword\fR 
.ig >>
<a href="attributetypes.html#text">
.>>
\fI text \fR
.ig >>
</a>
.>>
.IP
Allows the \fCshowvalues\fR label to be formatted.
The symbol \fC@@N\fR will be evaluated to the plottable value.
May also be used to label bars with a constant.
Example: \fClabelword: N=@@N\fR

.LP
\fBlabelfield\fR 
.ig >>
<a href="attributetypes.html#dfield">
.>>
\fI dfield \fR
.ig >>
</a>
.>>
.IP
If specified, the contents of the data field \fIdfield\fR will be used as the label.
The text may include embedded \fC@@N\fR (see above) and
\fC\\n\fR to symbolize newlines if longways labels are being done.

.LP
\fBlabelpos\fR
.ig >>
<a href="attributetypes.html#locvalue">
.>>
\fI locvalue \fR
.ig >>
</a>
.>>
.IP
If specified, controls the positioning of the labels.
For example, if doing vertical bars, this attribute would
control the vertical placement of bar labels.
(This attribute is new with version 1.33).
.br
Example: \fClabelpos: min-0.2\fR 

.LP
\fBbackbox\fR 
.ig >>
<a href="color.html">
.>>
\fI color \fR
.ig >>
</a>
.>>
.IP
If specified, a backing box of the given \fIcolor\fR will be 
rendered behind each end-of-bar label (not done for longways labels).  
This may be useful if the labels are hard to see because of bar color.

.LP
\fBlongwayslabel\fR \fCyes\fR | \fCno\fR
.IP
If \fCyes\fR, the label will be shown longways along the length of bars,
rather than near the tops.  This may be useful for showing longer labels.
Label text may include embedded newlines symbolized by \fC\\n\fR.

.ig >>
<br>
<br>
</td></tr>
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<a href="Welcome.html">
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<a href="../doc/Copyright.html">Copyright Steve Grubb</a>
<br>
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<center>
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</center>
</td></tr>
</table>
.>>
