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C00002 00002		Line Drawing Representation
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	Line Drawing Representation

To represent line drawings composed of straight lines, there are
several equivalent representations.

What operations does one do on these graphs?
  traversal
  connectivity
    shared edges
    regions
    interior
  geometry--angles at vertices

In generalizing, vertices by themselves are not so useful.  They don't
specify curves.

VERTICES AND CONNECTIVITY
  Everything about the line drawing can be determined (with some work)
  from this representation.
    an example:
		(v1 v2 v3 v4 ......)
      v1 location (x11,x12) connectivity (v2 v4)


MODIFIED VERTEX AND CONNECTIVITY (resembling "winged-edge")