# Converting polygon to graph in V7

I've unsuccessfully tried many ways of converting polygon points into a graph using Mathematica 7, and I am frustrated. I looked at this post, but it doesn't work:

Needs["Combinatorica"];
crds = {{1, 10}, {2, 4}, {10, 5}, {20, 10}};
vertices = Range[Length[crds]];

Graph[vertices, edges]


produces errors:

Syntax::sntxf: "\!$$\*StyleBox[\"\\\"\\\\\\\"\\\"\", \"MT\"]$$\!$$\*StyleBox[\! \(vertices$$, \"MT\"]\)\!$$\*StyleBox[\"\\\"\\\\\\\" cannot be followed by \\\\\\\" \\\"\", \"MT\"]$$\!$$\*StyleBox[\!\(\(\(\\[ DirectedEdge]$$\) $$\(RotateLeft[vertices]$$\)\), \"MT\"]\)\!$$\*StyleBox[\"\\\"\\\\\\\".\\\"\", \"MT\"]$$\!$$\*StyleBox[\! \(\"\"$$, \"MT\"]\)"

Syntax::tsntxi: "\!$$\*StyleBox[\"\\\"\\\\\\\"\\\"\", \"MT\"]$$\!$$\*StyleBox[\!\(\\[ DirectedEdge]$$, \"MT\"]\)\!$$\*StyleBox[\"\\\"\\\\\\\" is incomplete; more input is needed.\\\"\", \"MT\"]$$\!$$\*StyleBox[\!\(\"\"$$, \"MT\"]\)"

Syntax::sntxi: Incomplete expression; more input is needed.


Any ideas?

• The syntax of Graph in Combinatorica is Graph[e, v, opts], not Graph[v, e] as with the new built-in Graph. May 22, 2013 at 20:09

With Combinatorica, you should usually use MakeGraph rather than Graph directly. Here are some expressions that create the graph you want and which can be easily adapted for use with any graph that you've defined appropriate vertices and edges symbols for:

Needs["Combinatorica"]
crds = {{1, 10}, {2, 4}, {10, 5}, {20, 10}};
vertices = Range[Length[crds]];

Needs["Combinatorica"];
`