MATLAB: How to choose different colors for nodes

graphgraph theoryhighlightnodecolor

t = [1 1 1 1];
h = [2 3 4 5];
g = graph(t,h);
p = plot(g);
g.Edges.value = [10; 20; 20; 100];
g.Nodes.value = [0.3; 0.564; 12; 1; 0.005];
g.Nodes.NodeColors = g.Nodes.value;
g.Edges.EdgeColors = g.Edges.value;
p.NodeCData = g.Nodes.NodeColors;
p.EdgeCData = g.Edges.EdgeColors;
q= plot(g,'NodeCData',g.Nodes.NodeColors);
colorbar

t is the source node as input and h is demand node as output. I want to two different colors for input and output. But I don't find correct way. Plz help me to solve it.

Best Answer

When you call plot on your graph or digraph object, specify the 'NodeColor' property. For example, here are two ways to create a digraph like the one in your example and plot it with node 1 being red and the others being green. I put each in their own figure window so you can compare the results.

d = digraph;
d = addedge(d, 1, 2:5);

You can explicitly specify a numnodes(d)-by-3 matrix of RGB values:

figure
p = plot(d, 'NodeColor', [1 0 0; 0 1 0; 0 1 0; 0 1 0; 0 1 0]);

Or you can plot with all the nodes being the same color and highlight ones that are in some way 'special'.

figure;
h = plot(d, 'NodeColor', 'g');
highlight(h, 1, 'NodeColor', 'r');

Related Solutions

MATLAB: Coloring node and edge of a graph

The highlight function is one way to do this. Check out the examples on this page.

MATLAB: Delete and add new edges in a graph

A graph object is undirected. A digraph object is directed.

Construct your network graph using digraph instead of graph on the fourth line of your code.

By the way, the addedge function has two capabilities you might find useful.

The s (source) and t (target) inputs can be vectors to add multiple edges at once.
If the source and/or target inputs reference nodes that don't yet exist, addedge adds them.

So you could do this with something like:

% Make a digraph and plot it for later reference
G = digraph(triu(ones(3)));
figure;
plot(G)
% How many nodes does G have?
N = numnodes(G);
% Add 2 new nodes
newnodes = [N+1 N+2];
% Add the edges between 1 and N+1, N+1 and N+2, and N+2 and 2
%

% I'm doing this in a copy of G, rather than G itself so you can go back
% and compare G and G2. But you can modify G itself if you want.
%
% Because of the way I created G, it's a weighted digraph, so I need
% to give the new edges weights. I chose to weight them all pi.
% Scalar expansion lets me specify a scalar weight to be used for each new edge.
G2 = addedge(G, [1 newnodes], [newnodes 2], pi);
% Eliminate the edge from 1 to 2
G2 = rmedge(G2, 1, 2);
% Plot the new digraph
figure;
plot(G2)

Best Answer

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MATLAB: Coloring node and edge of a graph

MATLAB: Delete and add new edges in a graph

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