Attribute VB_Name = "Module1"
Type TreeObservation

 Plot_ID As Long
 Tree_id As Long
 STRS_Status As Long
 Field_Status As Long
 X As Double
 Y As Double
 SigmaX As Double
 sigmaY As Double
 Zbutt As Double
 Ztop_foto As Double
 Ztop_LiDAR As Double
 Sp_foto As Long
 Sp_ref As Long
 h_foto As Double
 h_LiDAR As Double
 Dcrm_foto As Double
 Dcrm_LiDAR As Double
 Dcrm_LiDAR_RMSE As Double
 d13_foto As Double
 d13_foto_LiDAR As Double
 d13_ref As Double
 Sample_tree As Long
 h_ref As Double
 h_ref_nasl As Double
 hc_ref As Double
 Usable As Long
 yNasl As Double
 v_ref As Double
 v_saw_ref As Double
 v_pulp_ref As Double
 v_waste_ref As Double
 
    
End Type

'Public T() As TreeObservation

Type PlotObs
  Plot_ID As Long
  X As Double
  Y As Double
  Npine As Long
  Nspruce As Long
  Nbroad As Long

End Type

Public Sub indexx(ByVal N As Long, ra() As Single, indx() As Long)

Rem Heapsort from Numerical recipes
Rem indx(1 to N) is an index table, returned
Rem ra(1 to N) is the data to be sorted, left as is.

Dim i As Long, j As Long, l As Long, ir As Long, indxt As Long
Dim q As Single
Dim apu As Integer

On Error GoTo virhe_sort

For j = 1 To N
 indx(j) = j
Next j

l = N / 2 + 1
ir = N

10:
 If (l > 1) Then
  l = l - 1
  indxt = indx(l)
  q = ra(indxt)
 Else
  indxt = indx(ir)
  q = ra(indxt)
  indx(ir) = indx(1)
  ir = ir - 1
   If (ir = 1) Then
    indx(1) = indxt
   Exit Sub
   End If
 End If
i = l
j = l + l
20: If j <= ir Then
     If j < ir Then
      If (ra(indx(j)) < ra(indx(j + 1))) Then j = j + 1
     End If
     If (q < ra(indx(j))) Then
      indx(i) = indx(j)
      i = j
      j = j + j
     Else
     j = ir + 1
     End If
     GoTo 20
    End If
   indx(i) = indxt
   GoTo 10
virhe_sort:
MsgBox ("Error in Heapsort, l is " & l)
End Sub