GraphViz Node Placement and Rankdir

Question

I'm having very good luck with graphviz and have been able to make nearly every graph that I need. I'm trying to duplicate this:

http://en.wikipedia.org/wiki/File:ICS_Structure.PNG

as faithfully as I can. The bottom part of that graph all flows top to bottom and I've got that working fine. What I have not been able to do is place the first 3 children right below "Incident Commander". They branch left and right. Plus note how the edges are shared in the top 8 nodes. Is that possible with dot? I can deal with everything else but not those top nodes. Can someone give me a clue to solve this?

Answer 1

Two useful techniques for reproducing graph layouts are:

• Invisible nodes
• Rank constraints

Here's a quick try for the top nodes:

digraph g{
ranksep=0.2;

node[shape=box3d, width=2.3, height=0.6, fontname="Arial"];
n1[label="Incident Commander"];
n2[label="Public Information\nOfficer"];
n3[label="Liaison Officer"];
n4[label="Safety Officer"];
n5[label="Operations Section"];
n6[label="Planning Section"];
n7[label="Logistics Section"];
n8[label="Finance/Admin. Section"];

node[shape=none, width=0, height=0, label=""];
edge[dir=none];
n1 -> p1 -> p2 -> p3;
{rank=same; n2 -> p1 -> n3;}
{rank=same; n4 -> p2;}
{rank=same; p4 -> p5 -> p3 -> p6 -> p7;}
p4 -> n5;
p5 -> n6;
p6 -> n7;
p7 -> n8;
}

And here's the result:

Answer 2

The native Graphviz (dot) rendering does not support the organogram rendering style used in the original. While it can generate orthogonal edges (as shown), there is no way to group edges. The vertical layering can be achieved with minlen.

The accepted answer is somewhat of an abuse of the notation, but altogether a reasonable approach.

The changes to the supplied solution are:

graph [splines=ortho]; edge [dir = none];

{ rank = same; n2; n3; }
n1 -> { n2; n3; };
n1 -> n4 [minlen = 2];
{ rank = same; n5; n6; n7; n8; };
n1 -> { n5; n6; n7; n8; } [minlen = 3];