Graphviz outputs a mess

Question

I'm trying to visualise the following data in dot format using GraphViz:

digraph n {
  node [nodesep=2.0, fontsize=11];
  graph [ overlap=false];
  edge[weight=0.2];
  A -> B [label="I/5"]
  A -> A [label="*/0"]
  A -> C [label="ii/2"]
  A -> H [label="vii/1"]
  B -> D [label="iii/1"]
  B -> E [label="IV/2"]
  B -> F [label="V/2"]
  B -> B [label="vi/2"]
  C -> F [label="V/2"]
  C -> H [label="vii/1"]
  D -> E [label="IV/2"]
  E -> D [label="iii/2"]
  E -> G [label="iv/1"]
  E -> F [label="V/3"]
  F -> B [label="I/4"]
  F -> B [label="vi/1"]
  F -> B [label="*/0"]
  G -> B [label="I/5"]
  H -> B [label="vi/1"]
}

Running the following command: neato -Tpng Chord_NFA.dot > Chord_NFA.png

gives me this output:

I'd like it to fit on A4 and for none of the edges to overlap or cross over a node. This is possible (mathematically) because I did it myself with a biro.

Try using `fdp` instead of `neato`; it takes longer, but produces better (more spaced-out) results. Some edges may still overlap nodes, however. — Phrogz, May 03 '12 at 20:33

score 39 · Answer 1 · answered May 03 '12 at 21:58

Here's a some steps in a better direction:

nodesep is not a node-attribute - and it probably doesn't do what you expected. But it still is useful in your case:

... this affects the spacing between loops on a single node, or multiedges between a pair of nodes.
I don't think edge weight changes something if you change it for all edges.
Enabling splines is often a good idea.
Adding additional space around the nodes can be done with sep
overlap has more values than true/false - I often find scalexy useful.
Once the node distribution is ok, you may fine-tune label positions by using a combination of headlabel/taillabel, labeldistance and labelangle (red in the example below to make them stand out).

Here's the modified sample:

digraph n {
splines=true;
sep="+25,25";
overlap=scalexy;
nodesep=0.6;
node [fontsize=11];
//edge[weight=0.2];

A -> B [label="I/5"]
A -> A [label="*/0"]
A -> C [label="ii/2"]
A -> H [label="vii/1"]
B -> D [label="iii/1"]
B -> E [label="IV/2"]
B -> F [headlabel="V/2", labeldistance=4, labelangle=-10, labelfontcolor=red]
B -> B [label="vi/2"]
C -> F [label="V/2"]
C -> H [label="vii/1"]
D -> E [label="IV/2"]
E -> D [label="iii/2"]
E -> G [label="iv/1"]
E -> F [headlabel="V/3", labeldistance=8, labelangle=-7, labelfontcolor=red]
F -> B [label="I/4"]
F -> B [label="vi/1"]
F -> B [label="*/0"]
G -> B [taillabel="I/5", labeldistance=4, labelangle=15, labelfontcolor=red]
H -> B [label="vi/1"]
}

graphviz output

Victor Stafusa - BozoNaCadeia · Accepted Answer · 2012-07-13T19:02:06.870

I played with it a few and got this:

digraph n {
  node [nodesep=2.0, fontsize=11];
  graph [overlap = false];
  subgraph cluster_a {
    style=invisible;
    A; B; H;
  }
  subgraph cluster_b {
    style=invisible;
    D; E; G;
  }
  subgraph cluster_c {
    style=invisible;
    C; F;
  }
  A -> B [label="I/5"];
  A -> A [label="*/0"];
  A -> C [label="ii/2"];
  A -> H [label="vii/1"];
  B:w -> D [label="iii/1"];
  B:nw -> E [minlen=3 label="IV/2"];
  B -> F [minlen=2 label="V/2"];
  B -> B [label="vi/2"];
  C -> F [minlen=2 label="V/2"];
  C -> H [label="vii/1"];
  D -> E [label="IV/2"];
  D -> E [minlen=2 dir=back label="iii/2"];
  G -> E [minlen=2 dir=back label="iv/1"];
  F -> E [dir=back label="V/3"];
  B -> F [minlen=2 dir=back label="I/4"];
  B -> F [minlen=2 dir=back label="vi/1"];
  B -> F [minlen=2 dir=back label="*/0"];
  B -> G [dir=back label="I/5"];
  H -> B [label="vi/1"];
}

Compile with:

dot -Tpng -o Chord_NFA.png Chord_NFA.gv

The output is this, without any line crossings:

graph

The trick is:

To add the minlen attribute to force some separation, giving more spacing for rendering without overlaps and crossings.
To invert the logic of some edges (rendering them uninverted with dir=back). This way, dot always sees an acyclic graph and can order the edges without getting confused.
Focusing in some subgraphs first and grouping their nodes in clusters to give they some "protection" from interference when rendering the rest of the graph.

score 8 · Answer 3 · answered May 23 '12 at 02:21

8

Using the dot engine I got the following output without changing the dot file which should fit on A4. Marapet's rendition does make better use of the space.

dot engine output

answered May 23 '12 at 02:21

ob1

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Graphviz outputs a mess

3 Answers3