' **********************************************************
' Overlap V2.AVE
' Finds overlaps.  Makes new shapefile which gives overlaps 
' to the smaller of the two polygons, and writes all other
' polygons normally.  Writes a comma-delimited file to keep
' record of the overlaps.
'
' Modified by Tim Thomas on 12/14/01.
'
' Based on Fast neighbors.ave
' It was written by Timothy S. Thomas.
' Editing began on 11/27/00, and was last edited on 11/27/00.
' It is based on "Find neighbors little program".

' **********************************************************
' Set up basic variables
' **********************************************************

theProject = av.GetProject
theView = av.GetActiveDoc
theThemeList = theView.GetActiveThemes
theTheme = theThemeList.Get(0)
theFTab = theTheme.GetFTab
numRecs = theFTab.GetNumRecords

' "Shape" is a special word in FTabs
shapeField = theFTab.FindField("Shape")


' **********************************************************
' This allows the user to pick a field as the basic unit for
' evaluation.
' **********************************************************

' Gets new field list, reflecting deletions of fields
fieldList = theFTab.GetFields.Clone
fieldList.Insert("<None>")
idField = MsgBox.ChoiceAsString(fieldList,"Select polygon ID field",
            "Poly ID field")


' **********************************************************
' Create a new shapefile to hold the corrected shapes and
' make a comma-delimited file to keep a record of the 
' corrections
' **********************************************************

' Shows message in message bar
av.ShowMsg("Creating overlap shapefile")

' Creates file
FTabFN = theFTab.GetSrcName.GetFileName
baseString = FTabFN.GetBaseName
extString = FTabFN.GetExtension
newString = FTabFN.AsString.Substitute(baseString,"")
new2String = baseString.Substitute(extString,"shp")
new3String = baseString.Substitute(extString,"csv")
newFTabFN = FileDialog.Put(
          (newString + "no overlaps " + new2String).AsFileName,
          "*.shp","No overlaps shapefile name")
newFTab = FTab.MakeNew(newFTabFN,Polygon) 
new2FTabFN = FileDialog.Put(
          (newString + "overlaps " + new2String).AsFileName,
          "*.shp","Overlaps shapefile name")
new2FTab = FTab.MakeNew(new2FTabFN,Polygon) 
newcsvFN = FileDialog.Put(
          (newString + "overlap record " + new3String).AsFileName,
          "*.csv","Data file name")
newcsvFile = LineFile.Make(newcsvFN,#FILE_PERM_WRITE) 

msg1 = "Divide by this to convert map units to area units"
areaconv = MsgBox.Input(msg1,"Converstion factor","10000").AsNumber
                                                 

' **********************************************************
' Clone fields for newFTab
' **********************************************************
newshapeField = newFTab.FindField("Shape")
inFields = theFTab.GetFields
newFields = List.Make
for each f in inFields
   if (f.GetName <> "shape") then
      newFields.Add(f.Clone)
   end
end
newFTab.AddFields(newFields)

new2shapeField = new2FTab.FindField("Shape")
new2idField = Field.Make("ItsctID", #FIELD_LONG, 8, 0)
id1Field = Field.Make("PolyID1", #FIELD_LONG, 8, 0)
id2Field = Field.Make("PolyID2", #FIELD_LONG, 8, 0)
new2FTab.AddFields({new2idField,id1Field,id2Field})


' **********************************************************
' Check the shapefile for overlaps
' **********************************************************

for each recnum in 0..(numRecs-1)

  thePoly = theFTab.ReturnValue(shapeField,recnum).Clean
  id = theFTab.ReturnValueString(idfield,recnum)
  area1 = (thePoly.ReturnArea / areaconv).SetFormat("d.dddddd")
  theFTab.SelectByPolygon(thePoly,#VTAB_SELTYPE_NEW)
  dcut = 0

  for each s in theFTab.GetSelection

   id2 = theFTab.ReturnValueString(idfield,s)
   
   if (id<>id2) then
   
    otherPoly = theFTab.ReturnValue(shapeField,s).Clean
    itsctShape = thePoly.ReturnIntersection(otherPoly)

    ' The GetDimension was supposed to only give a value of 2 if
    ' the intersection was a polygon.  In practice, it often
    ' gives a 2 if the intersection is an arc.  So, have to use area
    ' as the measure of whether it is a polygon.
    
    ' dim = itsctShape.GetDimension
    ' if (dim = 2) then
      
    area = itsctShape.ReturnArea.SetFormat("d.dddddd")

    ' The reason for doing the following second area computation 
    ' was that sometimes intersecting one way incorrectly returns 
    ' 0 for area.  It is commented out now because I was given
    ' the impression if I do a deep clean on the data before
    ' running this program, then I should not have a problem
    ' with area computation.  Also, because I now look only at 
    ' polygons, I should not have a problem with null values.

    '  if (area.IsNull) then
    '    area = otherPoly.ReturnIntersection(thePoly).ReturnArea
    '  end

    area = (area / areaconv)
    
    if (area.IsNull.Not) then

      area2 = (otherPoly.ReturnArea / areaconv).SetFormat("d.dddddd")


      ' Writing a line of output to the csv file

      if (id < id2) then
        theString = id + ", " + id2 + ", " + area.SetFormat("d.dddddddd").AsString + " , " 
          + area1.SetFormat("d.dddddddd").AsString + " , "  + area2.SetFormat("d.dddddddd").AsString
        newcsvFile.WriteElt(theString)
        new2rec = new2FTab.AddRecord
        new2FTab.SetValue(new2shapeField,new2rec,itsctShape)
        new2FTab.SetValue(new2idField,new2rec,new2rec+1)
        new2FTab.SetValue(id1Field,new2rec,id)
        new2FTab.SetValue(id2Field,new2rec,id2)
      end
        
        
      ' Adusting thePoly, if necessary
      
      if (area1 > area2) then
        newPoly = thePoly.ReturnDifference(itsctShape)
        thePoly = newPoly
      end
      
    end
    
   end

  ' This is the END for (each s in theFTab.GetSelection)
  end

  newrec = newFTab.AddRecord
  newFTab.SetValue(newshapeField,newrec,thePoly)
  for each fld in theFTab.GetFields
    fldName = fld.GetName
    if (fldName <> "shape") then
      newfld = newFTab.FindField(fldName)
      val = theFTab.ReturnValue(fld,newrec)
      newFTab.SetValue(newfld,newrec,val)
    end
  end

  av.SetStatus(100*(recnum+1)/numrecs)

end

' Clears selected features in the theme and theme table
theTheme.ClearSelection

' Clears message in message bar
av.ClearMsg

' Turns off editing in the FTab
newFTab.SetEditable(false)
newFTheme = FTheme.Make ( newFTab )
theView.AddTheme ( newFTheme )
new2FTab.SetEditable(false)
new2FTheme = FTheme.Make ( new2FTab )
theView.AddTheme ( new2FTheme )


' Removes garbage objects
av.PurgeObjects