gplot                  package:sna                  R Documentation

_T_w_o-_D_i_m_e_n_s_i_o_n_a_l _V_i_s_u_a_l_i_z_a_t_i_o_n _o_f _G_r_a_p_h_s

_D_e_s_c_r_i_p_t_i_o_n:

     'gplot' produces a simple two-dimensional plot of graph 'g' in
     stack 'dat'.  A variety of options are available to control vertex
     placement, display details, color, etc.

_U_s_a_g_e:

     gplot(dat, g = 1, gmode = "digraph", diag = FALSE, label = c(1:dim(dat)[2]),
         coord = NULL, jitter = TRUE, thresh = 0, usearrows = TRUE, mode = "segeo",
         displayisolates = TRUE, interactive = FALSE, boxed.labels = TRUE, 
         xlab = NULL, ylab = NULL, pad = 0.2, vertex.pch = 19, label.cex = 1,
         vertex.cex = 1, label.col = 1, edge.col = 1, vertex.col = 1,
         arrowhead.length = 0.2, edge.lty = 1, edge.lwd = 0, edge.len = 0.5,
         edge.curve = 0.1, edge.steps = 50, diag.size = 0.025, uselen = FALSE,
         usecurve = FALSE, suppress.axes = TRUE, new = TRUE, layout.par = NULL, ...)

_A_r_g_u_m_e_n_t_s:

     dat: a graph or graph stack.  This data may be valued. 

       g: integer indicating the index of the graph which is to be
          plotted.  By default, 'g==1'. 

   gmode: String indicating the type of graph being evaluated. 
          '"digraph"' indicates that edges should be interpreted as
          directed; '"graph"' indicates that edges are undirected;
          '"twomode"' indicates that data should be interpreted as
          bimodal (i.e., rows and columns are distinct vertex sets). 
          'gmode' is set to '"digraph"' by default. 

    diag: boolean indicating whether or not the diagonal should be
          treated as valid data.  Set this true if and only if the data
          can contain loops.  'diag' is 'FALSE' by default. 

   label: a vector of vertex labels, if desired; defaults to the vertex
          index number. 

   coord: user-specified vertex coordinates, in an NCOL(dat)x2 matrix. 
          Where this is specified, it will override the 'mode' setting. 

  jitter: boolean; should the output be jittered? 

  thresh: real number indicating the lower threshold for tie values. 
          Only ties of value >'thresh' are displayed.  By default,
          'thresh'=0.

usearrows: boolean; should arrows (rather than line segments) be used
          to indicate edges? 

    mode: the vertex placement algorithm; this must correspond to a
          'gplot.layout' function. 

displayisolates: boolean; should isolates be displayed? 

interactive: boolean; should interactive adjustment of vertex placement
          be attempted? 

boxed.labels: boolean; place vertex labels within boxes? 

    xlab: X axis label. 

    ylab: Y axis label. 

     pad: amount to pad the plotting range; useful if labels are being
          clipped. 

vertex.pch: character type for vertices; may be given as a vector, if
          vertices are to be of different types. 

label.cex: character expansion factor for label text. 

vertex.cex: character expansion factor for vertices; may be given as a
          vector, if vertices are to be of different types. 

label.col: color for vertex labels; may be given as a vector, if labels
          are to be of different colors. 

edge.col: color for edges; may be given as a vector or adjacency
          matrix, if edges are to be of different colors. 

vertex.col: color for vertices; may be given as a vector, if vertices
          are to be of different colors. 

arrowhead.length: arrowhead length to use with 'arrow', if
          'usearrows==TRUE'. 

edge.lty: line type for edges; may be given as a vector or adjacency
          matrix, if edges are to have different line types. 

edge.lwd: line width scale for edges; if set greater than 0, edge
          widths are given by 'edge.lwd*dat'.  May be given as a vector
          or adjacency matrix, if edges are to have different line
          widths. 

edge.len: if 'uselen==TRUE', curved edge lengths are scaled by
          'edge.len'. 

edge.curve: if 'usecurve==TRUE', the extent of edge curvature is
          controlled by 'edge.curv'.  May be given as a fixed value,
          vector, or adjacency matrix, if edges are to have different
          levels of curvature.  

edge.steps: for curved edges (including loops), the number of line
          segments to use for the curve approximation. 

diag.size: loop size, if 'diag==TRUE'. 

  uselen: boolean; should we use 'edge.len' to rescale edge lengths? 

usecurve: boolean; should we use 'edge.curve'? 

suppress.axes: boolean; suppress plotting of axes? 

     new: boolean; create a new plot?  If 'new==FALSE', vertices and
          edges will be added to the existing plot. 

layout.par: parameters to the 'gplot.layout' function specified in
          'mode'. 

     ...: additional arguments to 'plot'. 

_D_e_t_a_i_l_s:

     'gplot' is the standard network visualization tool within the
     'sna' library.  By means of clever selection of display
     parameters, a fair amount of display flexibility can be obtained. 
     Graph layout - if not specified directly using 'coord' - is
     determined via one of the various available algorithms.  These
     should be specified via the 'mode' argument; see 'gplot.layout'
     for a full list.  User-supplied layout functions are also possible
     - see the aforementioned man page for details.

     Note that where 'gmode=="twomode"', the supplied two-mode matrix
     is converted to bipartite adjacency form prior to computing
     coordinates.  If 'interactive==TRUE', then the user may modify the
     initial graph layout by selecting an individual vertex and then
     clicking on the location to which this vertex is to be moved; this
     process may be repeated until the layout is satisfactory.

_V_a_l_u_e:

     A two-column matrix containing the vertex positions as x,y
     coordinates.

_A_u_t_h_o_r(_s):

     Carter T. Butts buttsc@uci.edu 

     Alex Montgomery ahm@stanford.edu

_R_e_f_e_r_e_n_c_e_s:

     Wasserman, S. and Faust, K.  (1994)  _Social Network Analysis:
     Methods and Applications._  Cambridge: Cambridge University Press.

_S_e_e _A_l_s_o:

     'plot', 'gplot.layout'

_E_x_a_m_p_l_e_s:

     gplot(rgraph(5))               #Plot a random graph
     gplot(rgraph(5),usecurv=TRUE)  #This time, use curved edges
     gplot(rgraph(5),mode="mds")    #Try an alternative layout scheme

