function h = plotsom(W)
%PLOTSOM Plot the Self-Organizing Map in 2D
%
% PLOTSOM(W)
%
% Plot the Self-Organizing Map W, trained by som.m. This is only
% possible if the map is 2D.
%
% SEE ALSO
% SOM
% Copyright: D.M.J. Tax, davidt@ph.tn.tudelft.nl
% Faculty of Applied Physics, Delft University of Technology
% P.O. Box 5046, 2600 GA Delft, The Netherlands
% Maybe I should introduce the possibility to set the linewidth and
% markersize...
%
% Changes:
% DR1 - Dick de Ridder, 02-03-2006:
% If the mapped is trained on 3D data, plot it like this.
if ~ismapping(W)
error('I expect a SOM mapping!');
end
if ( ~strcmp(getmapping_file(W),'som') & ...
~strcmp(getmapping_file(W),'som_dd') )
error('I expect a SOM mapping!');
end
if size(W.data.neurons,2)~=2
error('The SOM can only be plotted in 2D');
end
% Get the data:
W = +W; w=W.neurons; k=W.k;
% Plot the bloody thing:
hold on;
% DR: Handle maps trained on 3D data.
if (size(w,2) == 3)
% The 'horizontal' lines:
for i=0:k(2)-1
h=plot3(w(i*k(1)+(1:k(1)),1),w(i*k(1)+(1:k(1)),2),w(i*k(1)+(1:k(1)),3),'o-');
set(h,'linewidth',2,'markersize',8);
end
I = reshape(1:k(1)*k(2),k(1),k(2))';
% The 'vertical' lines:
for i=0:k(1)-1
h=plot3(w(I(i*k(2)+(1:k(2))),1),w(I(i*k(2)+(1:k(2))),2),w(I(i*k(2)+(1:k(2))),3),'o-');
set(h,'linewidth',2,'markersize',8);
end
view(3);
else
% The 'horizontal' lines:
for i=0:k(2)-1
h=plot(w(i*k(1)+(1:k(1)),1),w(i*k(1)+(1:k(1)),2),'o-');
set(h,'linewidth',2,'markersize',8);
end
I = reshape(1:k(1)*k(2),k(1),k(2))';
% The 'vertical' lines:
for i=0:k(1)-1
h=plot(w(I(i*k(2)+(1:k(2))),1),w(I(i*k(2)+(1:k(2))),2),'o-');
set(h,'linewidth',2,'markersize',8);
end
end;
% Return the handle only when it is required
if (nargout==0)
clear h;
end
return