1 pixel wide area selection to line selection possible?

[Besonen, Mark]

Dear all,

I have a 1 pixel wide area selection (made with the wand tool) that represents a long, linear feature like a river.  I would like to turn this into a segmented or freehand line selection for length measurements.  I've searched around, and can't find a preexisting tool to do this.  Did I miss something obvious?  If the problem is unclear, let me know and I'll provide more details.  Thanks for your guidance.

Mark Besonen
TAMUCC