'============================================================================
'  ContArea.BAS
'  calculates the volume and area, saves the results to a file, opens the file 
'  in the worksheet and reads info about the area calcs. TB 20 DEC 95.
'  + Modified to do the area for a series of contours.   TB 27 Oct 98.
'  + Added prompt with grid zMin and zMax.               TB 04 Nov 98.
'============================================================================

'Open Surfer minimized.
'shell ("c:\surfer6\surfer32.exe",2)
' Create the Surfer application object.
Set Surf = CreateObject("Surfer.App")

'Variables
'---------
'UpSurf$ 
'zMin
'zMax
'zInt
'zValue
'WksHandle
'OutFile$
'PrevArea
'Xmin
'Xmax
'Ymin
'Ymax
'Zmin
'Zmax
'PosVol
'NegVol
'PosPlanArea
'NegPlanArea
'BlankedPlanArea
'PosSurfArea
'NegSurfArea

Top:
UpSurf$=InputBox$("Path and GRD file name or value for the 'Upper' Surface",\
  "Upper Surface","c:\surfer6\demogrid.grd")
if UpSurf$="" then end
'Calculate Volume report to get zMin zMax.
Surf.FileNew()
Surf.GridVolume(UpGrid=UpSurf$,Lowconstant=0) 
Surf.FileSaveAs("c:\surfer6\volume.dat")
Surf.FileClose() 'Close Volume Report Window
Surf.FileClose() 'Close Plot Window.
                  
'Open volume.dat in a worksheet window, store handle number.
WksHandle = Surf.FileOpen("c:\surfer6\volume.dat",1)

'Get the min and max Z.
Zmin$ = (Surf.GetWksCell(WksHandle,9,1)) 'B-10
Zmax$ = (Surf.GetWksCell(WksHandle,9,3)) 'D-10
Surf.FileClose() 'Close Volume Report Window
Surf.FileClose() 'Close Plot Window.

cMin = val(InputBox$("Enter minimum Z contour value.", "zMin",Zmin$))
cMax = val(InputBox$ ("Enter maximum Z contour value.","zMax",Zmax$))
cInterval = val(InputBox$("Enter the contour interval.","Contour Interval",\
  "5"))
if cInterval = 0 then end  
OutFile$ = InputBox$("Enter output filename for the area report.",\
  "Output File", "c:\surfer6\AreaOut.txt")
Open OutFile$ for output as #1  

PrevArea=0  
for cValue = cMin to cMax step cInterval
  Surf.FileNew()  'Open a plot window to calculate volume.
  Surf.GridVolume(UpGrid=UpSurf$,Lowconstant=cValue)
  'Save to a data file and close volume window.
  Surf.FileSaveAs("c:\surfer6\volume.dat")
  Surf.FileClose() 'Close Volume Report Window
  Surf.FileClose() 'Close Plot Window.
                  
  'Open volume.dat in a worksheet window, store handle number.
  WksHandle = Surf.FileOpen("c:\surfer6\volume.dat",1)

  'Get the volumes and areas.  Col A=0, Row 1=0.
  Xmin = val(Surf.GetWksCell(WksHandle,7,1)) 'B-8
  Xmax = val(Surf.GetWksCell(WksHandle,7,3)) 'D-8
  Ymin = val(Surf.GetWksCell(WksHandle,8,1)) 'B-9
  Ymax = val(Surf.GetWksCell(WksHandle,8,3)) 'D-9
  Zmin = val(Surf.GetWksCell(WksHandle,9,1)) 'B-10
  Zmax = val(Surf.GetWksCell(WksHandle,9,3)) 'D-10

  PosVol = Val(Surf.GetWksCell(WksHandle,21,3))
  NegVol = Val(Surf.GetWksCell(WksHandle,22,3))
  PosPlanArea = Val(Surf.GetWksCell(WksHandle,27,3))
  NegPlanArea = Val(Surf.GetWksCell(WksHandle,29,3))
  BlankedPlanArea = Val(Surf.GetWksCell(WksHandle,30,3))
  PosSurfArea = Val(Surf.GetWksCell(WksHandle,34,3))
  NegSurfArea = Val(Surf.GetWksCell(WksHandle,36,3))

    '  Print "Xmin = "; Xmin
    '  Print "Xmax = "; Xmax
    '  Print "Ymin = "; Ymin
    '  Print "Ymax = "; Ymax
    '  Print "Zmin = "; Zmin
    '  Print "Zmax = "; Zmax
    '  print
    '  Print "PosVol = ";PosVol 
    '  Print "NegVol = ";NegVol
    '  Print "Pos - Neg = "; PosVol-NegVol
  if cValue = cMin then
    print "==================================="
    print "          Area     Area      Area"
    print "Contour   Above    Below    Between"
    print " Value   Contour  Contour   Contours"
    print "-------  -------  -------   --------  "
    print #1, "       ,   Area     Area      Area"
    print #1, "Contour   Above    Below    Between"
    print #1, " Value   Contour  Contour   Contours"
    print #1, "-------  ------   ------    --------  " 
  else
    print     PrevArea - PosPlanArea
    print #1, PrevArea - PosPlanArea
  endif
  print     "   ";cValue;"    ";PosPlanArea;"  ";NegPlanArea;"  ";
  print #1, "   ";cValue;"    ";PosPlanArea;"  ";NegPlanArea;"  ";
  PrevArea=PosPlanArea
    '  Print "PosPlanArea = ";PosPlanArea
    '  Print "NegPlanArea = ";NegPlanArea
    '  Print "BlankedPlanArea = ";BlankedPlanArea
    '  Print "Total Plan Area = ";PosPlanArea + NegPlanArea + BlankedPlanArea
    '  Print "PosSurfArea = ";PosSurfArea
    '  Print "NegSurfArea = ";NegSurfArea
    '  Print "Total Surface Area = "; PosSurfArea + NegSurfArea

  Surf.FileClose()
next
print PosPlanArea  'Finish off the last line of the report.