NAME:
	ug_gr_wfc
 PURPOSE:
       Creates a ps or gif file containing plots of u-g vs g-r:
	ps.ps or .gif: All matched objects
	ps_m_52.ps or .gif: All matched objects with non zero 0.5-2 keV flux
	ps_m_41.ps or .gif: All matched objects with non zero 4.5-10 keV flux
	ps_all.ps or .gif: All WFC objects with synthetic data overlaid
		(in public XID directory)
	Outputs to screen or ps file or gif

 CALLING SEQUENCE:
	ug_gr_wfc,xmmdb,wfcdb,wfccat[,ps=ps,gif=gif,ionly=ionly,offmax=offmax,
		field=field]
 INPUTS:
	xmmdb:The xmm database to be searched. Must start with 'dbase/... '
	wfcdb: The wfc  "    	"	"	"	"	"
 	wfcat: catalogue file on which wfcdb is based 
		eg: 'wfc/izrgulockman_*.mer'
 OPTIONAL INPUT KEYWORDS:
	ionly: if set only objects with non-sero imag are searched in wfc db
		note this can only be called with an 'otherdb' containing
		and item labelled 'i'.
	offmax: STRING!!!!maximum offax angle of xmm objects to be matched. 
		If not set, all xmm objects are matched 
 OPTIONAL OUTPUT PARAMETERS:
	ps: file name of output ps file
	gif:file name of output gif file. Only active if ps is not set
		If neither set the output is sent to an IDL graphics window
	field:name of field (if directory in named after field)
 EXAMPLE:
	ug_gr_wfc,'xmm','wfc',xmmno[,offmax='5.0',ps='col_wfc_5to10.ps']
 CALLED PROCEDURES:
	match_obj, astrolib procedures,select_classes,avoid_offplot,select_cond
	ogif,cgif,ops,cps
 MODIFICATION HISTORY:
	31-Oct-2000  Original by Suzanne Aigrain
	07-Nov-2000  S. Aigrain: determines range itself

(See /home/xmmssc/soft/idl/pro/colplots/ug_gr_wfc.pro)