'DLGShape -- 8/4/98
'AV3.x DLG to Shapefile Script
'Version 2.1a:  Individual version
'Revisions:  supports unCHOPPED files

'This Avenue script converts Optional Format DLG-3 lines, points
'(degenerate lines), or polys to a shapefile, with attributes.
'Sorry, nodes are not supported.

'DLGShape assumes that the DLG file is uncompressed.  Optionally, the
'file may be preprocessed to 80 character lines of text.  Public domain
'processing software (GZIP and CHOP) may be obtained via the Internet:

'   http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/public.html

'Mark Cederholm
'plp@pierssen.com
'=======================================================================
'Home brew software, home brew beer -- Yahoo!!!!
'=======================================================================

'**** get input file

dlg_name = FileDialog.Show("*.dlg", "DLG Optional Format", "Import DLG")
if (dlg_name = nil) then
  exit
end

'**** get feature type to convert

OptionList = {"Line","Polygon","Point"}
GetFeature = MsgBox.ChoiceAsString(Optionlist,"Feature:","Import DLG")
if (GetFeature = nil) then
   exit
elseif (GetFeature = "Polygon") then
   skipfirst = MsgBox.MiniYesNo("Skip first polygon?",true)
end

'**** get output file

out_name = dlg_name.clone
out_name.SetExtension("shp")
out_name = FileDialog.Put(out_name, "*.shp", "Output Shapefile")
if (out_name = nil) then
  exit
end

'*** ask if file has been CHOPped

isChopped = MsgBox.MiniYesNo("Has the file been CHOPped?",true)

'**** skip to first record to process

if (isChopped) then
   dlg_file = LineFile.Make(dlg_name, #FILE_PERM_READ)
   FileLines = dlg_file.GetSize
   rblank = nil
else
   dlg_file = TextFile.Make(dlg_name, #FILE_PERM_READ)
   FileLines = dlg_file.GetSize / 80
   rblank = ""
end

if (GetFeature = "Polygon") then
   HeaderID = "A"
else
   HeaderID = "L"
end
av.ClearMsg
av.ClearStatus
av.ShowMsg("Reading File Data...")
if (isChopped) then
   record = dlg_file.ReadElt
else
   record = dlg_file.Read(80)
end
InputLine = 1
av.SetStatus(100*Inputline/Filelines)
while (record.Extract(0) <> HeaderID)
   if (isChopped) then
      record = dlg_file.ReadElt
   else
      record = dlg_file.Read(80)
   end
   InputLine = InputLine + 1
   av.SetStatus(100*InputLine/FileLines)
end

'**** process area records

'**** in this approach, the Shapefile is created minus the Shape value
'**** a list of lists of line IDs is created which will be used later
'**** in assembling the polygons

if (GetFeature = "Polygon") then
   PShape = FTab.MakeNew(out_name, Polygon)
   fields = List.Make
   fields.Add(Field.Make("id",#FIELD_LONG,11,0))
   PShape.AddFields(fields)
   PLineList = List.Make
   numpairs = 0
   numpolys = 0
   PolyRead = true
   while (PolyRead)

      '**** get poly ID and number of lines

      PolyID = record.Middle(1,5).AsNumber
      numlines = record.Middle(36,6).AsNumber

      '**** read remainder of poly record

      polyrec = List.make
      NotDone = true
      while (NotDone)
         if (isChopped) then
            record = dlg_file.ReadElt
         else
            record = dlg_file.Read(80)
         end
         InputLine = InputLine + 1
         av.SetStatus(100*InputLine/FileLines)
         if (record.Extract(0) = "L") then
            NotDone = false
            PolyRead = false
         elseif (record.Extract(0) = "A") then
            NotDone = false
         else
            polyrec.Merge(record.AsTokens(" "))
         end
      end
      if ((PolyID = 1) and (skipfirst)) then

         '**** skip first poly

         continue
      end
      rlist = List.Make
      j = 1
      while (j <= numlines)
         lineID = polyrec.Get(j - 1).AsNumber
         rlist.Add(lineID)
         j = j + 1
      end
      PLineList.Add(rlist)
      recno = PShape.AddRecord
      PShape.SetValue(PShape.FindField("id"),recno,PolyID)
      numpolys = numpolys + 1

      '**** add code pairs, if any, to feature table

      CodePairs = (polyrec.Count - numlines) / 2
      fields = List.Make
      while (CodePairs > numpairs)
         numpairs = numpairs + 1
         fields = List.Make
         fields.Add(Field.Make("major"+numpairs.AsString,#FIELD_LONG,6,0))
         fields.Add(Field.Make("minor"+numpairs.AsString,#FIELD_LONG,6,0))
         PShape.AddFields(fields)
      end
      k = 1
      while (k <= CodePairs)
         l = numlines + ((k - 1) * 2)
         major = polyrec.Get(l).AsNumber
         minor = polyrec.Get(l + 1).AsNumber
         PShape.SetValue(PShape.FindField("major"+k.AsString),recno,major)
         PShape.SetValue(PShape.FindField("minor"+k.AsString),recno,minor)
         k = k + 1
      end
   end
end

'**** process line records

'**** if the final product is to consist of polygons,
'**** the line records will be processed into a list of point lists
'**** otherwise the final shape file will be built on the fly

if (GetFeature = "Polygon") then
   LineList = List.Make
else
   if (GetFeature = "Line") then
      LShape = FTab.MakeNew(out_name, Polyline)
   else
      LShape = FTab.MakeNew(out_name, Point)
   end
   fields = List.Make
   fields.Add(Field.Make("id",#FIELD_LONG,11,0))
   LShape.AddFields(fields)
   numpairs = 0
end
while (record <> rblank)

   '**** get line ID and number of points

   lineID = record.Middle(1,5).AsNumber
   numpoints = record.Middle(42,6).AsNumber

   '**** read remainder of line record

   linerec = List.make
   NotDone = true
   while (NotDone)
      if (isChopped) then
         record = dlg_file.ReadElt
      else
         record = dlg_file.Read(80)
      end
      InputLine = InputLine + 1
      av.SetStatus(100*InputLine/FileLines)
      if (record = rblank) then
         NotDone = false
      else
         if (record.Extract(0).IsNumber) then
            linerec.Merge(record.AsTokens(" "))
         else
            NotDone = false
         end
      end
   end

   '**** create point list

   plist = list.make
   i = 1
   while (i <= numpoints)
      j = (i - 1) * 2
      x = linerec.Get(j).AsNumber
      y = linerec.Get(j + 1).AsNumber
      p1 = Point.Make(x,y)
      plist.Add(p1)
      i = i + 1
   end

   '**** check for degenerate line

   NotDegenerate = true
   if (plist.count = 2) then
      p1 = plist.Get(0)
      p2 = plist.Get(1)
      if (p1 = p2) then
         NotDegenerate = false
      end
   end
   if (NotDegenerate) then
      if (GetFeature = "Point") then
         DoShape = false
         DoAttributes = false
      elseif (GetFeature = "Line") then
         DoShape = true
         DoAttributes = true
      else
         DoShape = true
         DoAttributes = false
      end
   else
      if (GetFeature = "Point") then
         DoShape = true
         DoAttributes = true
      elseif (GetFeature = "Line") then
         DoShape = false
         DoAttributes = false
      else
         DoShape = false
         DoAttributes = false
      end
   end

   '**** update line/point shapefile or dictionary

   if (DoShape) then
      if (GetFeature = "Line") then
         plistl = List.Make
         pline = PolyLine.Make(plistl.Add(plist))
         recno = LShape.AddRecord
         LShape.SetValue(LShape.FindField("shape"),recno,pline)
         LShape.SetValue(LShape.FindField("id"),recno,lineID)
      elseif (GetFeature = "Point") then
         recno = LShape.AddRecord
         LShape.SetValue(LShape.FindField("shape"),recno,plist.Get(0))
         LShape.SetValue(LShape.FindField("id"),recno,lineID)
      else
         while (Linelist.Count < lineID)
            LineList.Add(nil)
         end
         LineList.Add(plist)
      end
   end

   '**** add code pairs, if any, to feature table

   if (DoAttributes) then
      CodePairs = (linerec.Count / 2) - numpoints
      fields = List.Make
      while (CodePairs > numpairs)
         numpairs = numpairs + 1
         fields = List.Make
         fields.Add(Field.Make("major"+numpairs.AsString,#FIELD_LONG,6,0))
         fields.Add(Field.Make("minor"+numpairs.AsString,#FIELD_LONG,6,0))
         LShape.AddFields(fields)
      end
      i = 1
      while (i <= CodePairs)
         j = (numpoints * 2) + ((i - 1) * 2)
         major = linerec.Get(j).AsNumber
         minor = linerec.Get(j + 1).AsNumber
         LShape.SetValue(LShape.FindField("major"+i.AsString),recno,major)
         LShape.SetValue(LShape.FindField("minor"+i.AsString),recno,minor)
         i = i + 1
      end
   end
end
dlg_file.close

'**** assemble polygons

if (GetFeature = "Polygon") then
   av.ClearMsg
   av.ClearStatus
   av.ShowMsg("Assembling Polygons...")
   item = 1
   for each recno in PShape
      av.SetStatus(100*item/numpolys)
      polyrec = PLineList.Get(item-1)
      numlines = polyrec.Count
      rlistl = List.Make
      rlist = List.Make
      j = 1
      while (j <= numlines)
         lineID = polyrec.Get(j - 1)
         if (lineID > 0) then

            '*** get pointlist entry and drop endpoint

            rlist.Merge(LineList.Get(lineID))
            rlist.Remove(rlist.Count - 1)

         elseif (lineID < 0) then

            '**** get pointlist entry, reverse order, and drop endpoint

            temp1list = LineList.Get(lineID.Abs)
            temp2list = List.Make
            k = temp1list.Count
            while (k >= 1)
               temp2list.Add(temp1list.Get(k - 1))
               k = k - 1
            end
            rlist.Merge(temp2list)
            rlist.Remove(rlist.Count - 1)
         else

            '**** add ring and prepare for the next

            rlistl.Add(rlist)
            rlist = List.Make
         end
         j = j + 1
      end
      rlistl.Add(rlist)
      poly = Polygon.Make(rlistl)
      PShape.SetValue(PShape.FindField("shape"),recno,poly)
      item = item + 1
   end
end
av.ClearMsg
av.ClearStatus
MsgBox.Info("Done.","DLGShape")

'=======================================================================