ploticus: proc legendentry

## proc legendentry | Welcome Gallery Handbook |
| Manual page for proc_legendentry(PL)

## DESCRIPTION

Defines one legend entry.`` This entry will be rendered the next time that proc legend is executed.`` Usually, legends are built by successive plotting procs having a `legendlabel` attribute. However, if additional flexibility is needed to make custom legend entries, this proc may be invoked, once per legend entry.``

For example, if a scatterplot is being created with various sized points, there is no automatic way to get a legend of the various point sizes, so proc legendentry could be executed (probably several times) to define legend information, then proc legend could be executed to render it.``

proc legendentry is also useful in setting up legend-driven plots which allow things like bar color, or scatterplot symbol color, size, or shape to be controlled by a data field.``

## EXAMPLE

See the gallery example scatterplot3a

## PREREQUISITES

None.``

## MANDATORY ATTRIBUTES

None.

## ATTRIBUTES

sampletype t

  The type of sample to be displayed with the entry.`` t may be one of: `line`, `color` , `symbol` , `text` , `line+symbol` , or `text+symbol`, or `none`.``
  `none` may be used to insert spacing or text headers/separators into the legend.``
  Example: `sampletype: text`

label text

  The label for the entry.`` Example: `label: Eastern counties`

tag string

  An optional short identifier to be associated with the entry, so that the entry can be accessed later.`` Used with proc bars colorfield, as in this example: colorfld

details text

  Details regarding the rendering of the sample.`` What this is depends on the `sampletype`.
  For `line`, a linedetails specification should be given.``
  For `color`, a color should be given.``
  For `symbol`, a symboldetails specification should be given.``
  For `text`, the character or word should be given here, and a textdetails specification may be given using the `details2` attribute.``
  For `line+symbol`, a linedetails specification should be given here, and a symboldetails specification given using the `details2` attribute.``
  For `text+symbol`, the character or word should be given here, a textdetails specification should be given using the `details2` attribute, and a symboldetails specification given using the `details3` attribute.``
  If `sampletype` is `none`, nothing should be given for this attribute.``

details2 text

  Secondary details attribute. See `details` above.``

details3 text

  See `details` above.``

## LEGEND-DRIVEN TECHNIQUE

"Legend-driven technique" allows bar color, scatterplot symbol, etc. to be controlled by a data field.`` This technique involves defining a legend first, containing information to associate data field contents with appearance details.`` Then the plotting is done.``

Here is the procedure:

  1. For every expected variation, set up an explicit legend entry using proc legendentry.`` `label`, `tag`, and `details` attributes should be supplied.`` The `tag` will be compared with data field contents.`` The `details` attributes control appearance.``
  2. Plot, using the appropriate attribute. For example, if you are doing a bar graph where individual bar colors are controlled by a data field, you would use proc bars and specify a `colorfield`.``

Examples of legend-driven technique are colorfld symfld symfld dupsleg
data display engine
Copyright Steve Grubb

Markup created by unroff 1.0, `` `` December 10, 2002.