'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 Sim sim@ecoline.ru (field name & multiple themes added)

theView    = av.GetActiveDoc
thmList = theView.GetActiveThemes

for each thmThemeIn in thmList

 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