planes

 PLANES Draws 2D component planes

 CALLS
 [hfig,hbar] = planes(smap)
 [hfig,hbar] = planes(smap,plottype)
 [hfig,hbar] = planes(smap,featset)
 [hfig,hbar] = planes(smap,featset,plottype)
 [hfig,hbar] = planes(u,feat)
 [hfig,hbar] = planes(u,feat,featnames)
 [hfig,hbar] = planes(u,feat,plottype)
 [hfig,hbar] = planes(u,feat,featnames,plottype)
 [hfig,hbar] = planes(u,feat,featnames,plottype,limits)

 Notation:
         P = Number of features
         S = Number of lattice points

 smap:      Som structure
 plottype:  String specifying the type of plot. Can be either:
               'image':   Colormap image plot type (default)
               'contour': Contour line plot type
               'surface': Surface plot type
 featset:   Set of features to be plotted. Can be specified either as an
            index vector or as a cell with the strings of the feature names
            to be plotted. By default all the features are plotted.
 u:         Grid data matrix (2 x S). Each column represents a grid node
 feat:      Features data matrix (P x S). Each row is a feature. Each 
            column can be see as the coordinates of a codebook vector
 featnames: Cell array {1 x P} with the names of the features to be
            represented. Default: {'Feature 1','Feature 2',...}
 limits:    Two column matrix (P x 2) with the limits for each of the P variables