chart.StackedBar    package:PerformanceAnalytics    R Documentation

_c_r_e_a_t_e _a _s_t_a_c_k_e_d _b_a_r _p_l_o_t

_D_e_s_c_r_i_p_t_i_o_n:

     This creates a stacked column chart with time on the horizontal
     axis and values in categories.  This kind of chart is commonly
     used for showing portfolio 'weights' through time, although the
     function will plot any values by category.

_U_s_a_g_e:

     chart.StackedBar(w, colorset = NULL, space = 0.2, cex.axis=0.8, cex.legend = 0.8, cex.lab = 1, cex.labels = 0.8, cex.main = 1, xaxis=TRUE, legend.loc="under",  element.color = "darkgray", unstacked = TRUE, xlab="Date", ylab="Value", ylim=NULL, date.format = "%b %y", major.ticks='auto', minor.ticks=TRUE, las = 0, xaxis.labels = NULL, ... )

_A_r_g_u_m_e_n_t_s:

       w: a matrix, data frame or zoo object of values to be plotted. 
          Rownames should contain dates or period labels; column names
          should indicate categories.  See examples for detail. 

colorset: color palette to use, set by default to rational choices 

   space: the amount of space (as a fraction of the average bar width)
          left before each bar, as in 'barplot'. Default is 0.2. 

cex.legend: The magnification to be used for sizing the legend relative
          to the current setting of 'cex', similar to 'plot'. 

cex.labels: The magnification to be used for event line labels relative
          to the current setting of 'cex'.  

 cex.lab: The magnification to be used for x- and y-axis labels
          relative to the current setting of 'cex'.  

cex.main: The magnification to be used for the chart title relative to
          the current setting of 'cex'. 

   xaxis: If true, draws the x axis 

    ylab: Set the y-axis label, same as in 'plot' 

date.format: Re-format the dates for the xaxis; the default is "%m/%y" 

major.ticks: Should major tickmarks be drawn and labeled, default
          'auto'

minor.ticks: Should minor tickmarks be drawn, default TRUE

xaxis.labels: Allows for non-date labeling of date axes, default is
          NULL 

cex.axis: The magnification to be used for sizing the axis text
          relative to the current setting of 'cex', similar to 'plot'. 

     las: sets the orientation of the axis labels, as described in
          'par'.  Defaults to '3'. 

legend.loc: places a legend into a location on the chart similar to
          'chart.TimeSeries'. The default, "under," is the only
          location currently implemented for this chart.  Use 'NULL' to
          remove the legend. 

element.color: provides the color for drawing less-important chart
          elements, such as the box lines, axis lines, etc. 

unstacked: logical.  If set to 'TRUE' _and_ only one row of data is
          submitted in 'w', then the chart creates a normal column
          chart.  If more than one row is submitted, then this is
          ignored.  See examples below. 

    xlab: the x-axis label, which defaults to 'NULL'. 

    ylim: set the y-axis limit, same as in 'plot' 

     ...: arguments to be passed to 'barplot'. 

_D_e_t_a_i_l_s:

     This function is a wrapper for 'barplot' but adds three additional
     capabilities.  First, it calculates and sets a bottom margin for
     long column names that are rotated vertically.  That doesn't
     always result in the prettiest chart, but it does ensure readable
     labels.  

     Second, it places a legend "under" the graph rather than within
     the bounds of the chart (which would obscure the data).  The
     legend is created from the column names.  The default is to create
     the legend when there's more than one row of data being presented.
      If there is one row of data, the chart may be "unstacked" and the
     legend removed.

     Third, it plots or stacks negative values from an origin of zero,
     similar to the  behavior of 'barchart' from the 'lattice' package.

_V_a_l_u_e:

     Plots a column chart or stacked column chart to the current
     device.

_N_o_t_e:

     The 'w' attribute is so named because this is a popular way to
     show portfolio weights through time.  That being said, this
     function isn't limited to any particular values and doesn't
     provide any normalization, so that the chart can be used more
     generally.

     The principal drawback of stacked column charts is that it is very
     difficult for the reader to judge size of 2nd, 3rd, etc., data
     series because they do not have common baseline.  Another is that
     with a large number of series, the colors may be difficult to
     discern.  As alternatives, Cleveland advocates the use of trellis
     like displays, and Tufte advocates the use of small multiple
     charts.

_A_u_t_h_o_r(_s):

     Peter Carl

_R_e_f_e_r_e_n_c_e_s:

     Cleveland, W.S. (1994), The Elements of Graphing Data, Summit, NJ:
     Hobart Press.

     Tufte, Edward R. (2001) The Visual Display of Quantitative
     Information, 2nd edition. The Graphics Press, Cheshire,
     Connecticut. See http://www.edwardtufte.com for this and other
     references.

_S_e_e _A_l_s_o:

     'barplot', 'par'

_E_x_a_m_p_l_e_s:

     data(weights)
     head(weights)

     # With the legend "under" the chart
     chart.StackedBar(weights, date.format="%Y", cex.legend = 0.7, colorset=rainbow12equal)

     # Without the legend
     chart.StackedBar(weights, colorset=rainbow12equal, legend.loc=NULL)

     # for one row of data, use 'unstacked' for a better chart
     chart.StackedBar(weights[1,,drop=FALSE], unstacked=TRUE, las=3)