----- file created by makedoc on: Tue Feb 11 14:15:26 2003
----- Documentation for /scisoft/IDL/scisoft/xaid/src//getedge.pro -----

 NAME:
	GETEDGE

 PURPOSE:
	This function calculates the EDGE of a curve

 CATEGORY:
	XAID package

 CALLING SEQUENCE:

	value = getedge(set [,value])

 INPUTS:
	set: a fltarr(2,npts) with the curve

 OPTIONAL INPUTS:
	value: a float number in the (0,1] interval indicating the 
		height level for the curve edge.

 KEYWORD PARAMETERS:
	GROUP = The widget ID of the widget that calls GETEDGE.
		When this ID is specified, and GETEDGE fails to calculate
		a result, them a widget message appears.

 OUTPUTS:
	The EDGE value

 PROCEDURE:
	Straightforward

 EXAMPLE:

		set = fltarr(2,100) 
		set[0,*] = findgen(100)+1 & set[1,*]=sin(!pi*set[0,*]/100)
		a = GetEdge(set,0.8)
		print,a

 MODIFICATION HISTORY:
 	Written by:	M. Sanchez del Rio.
	November 2nd, 1998. Based on GetFWHM()	


