'This script use the unit and projection setted by View Propertied to calculated 
'polygon area, the results are added as new field to the theme. 
'Copyright@ zhou, Japan zhou@ies.kyushu-u.ac.jp
'Modified by Maxim Dubinin sim@gis-lab.info (field name & multiple themes added)

theView    = av.GetActiveDoc
thmList = theView.GetActiveThemes

for each thmThemeIn in thmLis
 aPrj = theView.GetProjection
 ftbOutput = thmThemeIn.getftab
 ftbOutput.SetEditable(true)
 newAreaField = MsgBox.Input("Enter a name for the new AREA field (up to 8 characters):","Area","Area")
 if (newAreaField = Nil) then
   exit
 end

fidAreaOut = ftbOutput.FindField(newAreaField)
if(fidAreaOut = nil) then
    fieldname = newAreaField
    ftbOutput.AddFields({Field.Make(fieldname, #FIELD_FLOAT, 20, 5)})
else
    fidAreaOut = ftbOutput.FindField(newAreaField)
end

IDout = ftbOutput.FindField("WID")  
if(IDout = nil) then
	fieldname = "WID"
	ftbOutput.AddFields({Field.Make(fieldname, #FIELD_LONG, 8, 0)})
else
	IDout = ftbOutput.FindField("WID")
end

IDout = ftbOutput.FindField("WID")
p = 0
for each r in ftbOutput
	p = p + 1
    nRecNew = p - 1
    ftbOutput.SetValue(IDout,nRecNew,nRecNew)
end

if (thmThemeIn.GetFTab.GetSelection.Count > 0) then
  polyToProcess = thmThemeIn.GetFTab.GetSelection
else
  polyToProcess = thmThemeIn.GetFTab
end

fldShapeIn  = thmThemeIn.GetFTab.FindField("shape")
fidAreaOut    = ftbOutput.FindField(newAreaField)

'Begin processing
polycount = 0
for each r in polyToProcess
	polycount = polycount + 1
	polyin = thmThemeIn.GetFTab.ReturnValue(fldShapeIn,r)
	polyID = polycount
	llength = polyin.returnlength
	polyin1 = polyin.ReturnProjected (aPrj)
	aarea = polyin1.ReturnArea 
	nRecNew = ftbOutput.ReturnValue(IDout, r)
	ftbOutput.SetValue(fidAreaOut,nRecNew,aarea)
end
ftbOutput.RemoveFields({IDout})
end