information:filtering, quality:correction
Planar graph density

The meshedness coefficient or density D of a planar graph, or network, is the ratio of the number f – 1 of bounded faces (the same as the circuit rank of the graph, by Mac Lane's planarity criterion) by its maximal possible values 2 v – 5 for a graph with v vertices:

The density obeys 0 ≤ D ≤ 1, with D = 0 for a completely sparse planar graph (a tree), and D = 1 for a completely dense (maximal) planar graph.