Make polyline features look smoother using Avenue

Summary

Polylines with very few vertices can look blocky. You can smooth the appearance of these lines by creating more gentle curves; this is know as a spline operation. Spline adds more vertices at places where the line changes direction. This article provides two Avenue scripts that spline selected polyline or polylinez features of the first active theme of the active view.

Procedure

1. Open a new script window.
   
   
   A. Activate the Project window.
   B. Click the Scripts icon.
   C. Click New.
   
   
   
2. Paste the following code into the new script window:
   
   

   Code:
   '-- SPLINE POLYLINE FEATURES
   '
   '-- spline_polyline.ave
   '
   '-- This script uses a basic combination of densifying the 
   '-- polyline and implementing the Bezier's spline
   '-- method on the polyline.  This script needs a view
   '-- and the target theme active.
   
   '-- A combination of these two variables will produce different
   '-- results depending on the nature and scale of the Polyline.
   densityfactor = 0.025         '-- 0.000 to 1.000 only
   iterations    = 15            '-- 1 to 100 works best
   
   v = av.getactivedoc
   vg = v.getgraphics
   thm = v.getactivethemes.get(0)
   ftb = thm.getftab
   if(ftb.getshapeclass.getclassname <> "PolyLine") then
     msgbox.error("We can only spline PolyLine features.","")
     return nil
   end
   
   for each selrec in ftb.getselection
   
     thepolyline = ftb.returnvalue(ftb.findfield("Shape"),selrec)
       
     howdense = thepolyline.returnlength*densityfactor
     oldplist = thepolyline.returndensified(howdense).aslist
     
     newplist = {}
     for each apart in oldplist
       for each ap in apart
         newplist.add(ap)
       end
     end
     
     for each x in 1..iterations 
       newerplist = {}  
       for each i in 0..(newplist.count-1)
         if(i = 0) then
           newerplist.add(newplist.get(i))
         elseif(i = (newplist.count-1)) then
           newerplist.add(newplist.get(i))
           break
         end        
         newp = line.make(newplist.get(i),newplist.get(i+1)).returncenter 
         newerplist.add(newp)  
       end
       newplist = newerplist.deepclone  
     end
     
     newpolyline = polyline.make({newplist})  
   
     gs = graphicshape.make(newpolyline)
     asymbol = symbol.make(#SYMBOL_PEN)
     asymbol.setsize(2)
     asymbol.setcolor(color.getred)
     gs.setsymbol(asymbol)
     vg.add(gs)
   end
   v.invalidate
   

   
   
3. Attach the script to the button on the View GUI.
   
   
   A. Compile the script.
   B. Switch to the Project window.
   C. Select Customize from the Project menu.
   D. On the Customize dialog box, click the Type dropdown arrow and click View.
   E. Select Buttons under Category.
   F. Click the New button.
   G. Double-click the Click property in the Customize dialog box.
   H. Type the name of the script in the Script Manager and click Select.
   I. Close the Customize dialog box.
   
   For more information, see "Customize dialog box" in ArcView Help.
   
   
4. Open the view and make the polyline theme active.
5. Select the polyline features to spline.
6. Click the new button. The script will create a graphic polyline.
   
   

   Note:
   For polylinez features, use the same steps above, except turn on the 3D Analyst extension and use the code below.

   
   
   

   Code:
   '-- SPLINE POLYLINE OR POLYLINEZ FEATURES:
   '
   '-- spline_polylinez.ave
   '
   '-- This script uses a basic combination of densifying the 
   '-- polyline and implementing the Bezier's spline
   '-- method on the polyline.  This script needs a view
   '-- and the target theme active.
   
   '-- Note: The 3D Analysis Extension must be loaded
   '
   
   '-- A combination of these two variables will produce
   '-- different results depending on the nature and scale of the Polyline.
   densityfactor = 0.025         '-- 0.000 to 1.000 only
   iterations = 15               '-- 1 to 100 works best
   
   v = av.getactivedoc
   vg = v.getgraphics
   thm = v.getactivethemes.get(0)
   ftb = thm.getftab
   if(ftb.getshapeclass.getclassname = "PolyLine") then
     hasz = false
   elseif(ftb.getshapeclass.getclassname = "PolyLineZ") then
     hasz = true
   else
     msgbox.error("We can only spline PolyLine of PolyLineZ features.","")
     return nil
   end
   
   for each selrec in ftb.getselection
   
     thepolyline = ftb.returnvalue(ftb.findfield("Shape"),selrec)
       
     howdense = thepolyline.returnlength*densityfactor
     oldplist = thepolyline.returndensified(howdense).aslist
     
     newplist = {}
     for each apart in oldplist
       for each ap in apart
         newplist.add(ap)
       end
     end
     
     for each x in 1..iterations 
       newerplist = {}  
       for each i in 0..(newplist.count-1)
         if(i = 0) then
           newerplist.add(newplist.get(i))
         elseif(i = (newplist.count-1)) then
           newerplist.add(newplist.get(i))
           break
         end        
         if(hasz) then
           newp = linez.make(newplist.get(i),newplist.get(i+1)).returncenter 
         else
           newp = line.make(newplist.get(i),newplist.get(i+1)).returncenter 
         end
         newerplist.add(newp)  
       end
       newplist = newerplist.deepclone  
     end
     
     if(hasz) then  
       newpolyline = polylinez.make({newplist})  
     else
       newpolyline = polyline.make({newplist})  
     end
   
     gs = graphicshape.make(newpolyline)
     asymbol = symbol.make(#SYMBOL_PEN)
     asymbol.setsize(2)
     asymbol.setcolor(color.getred)
     gs.setsymbol(asymbol)
     vg.add(gs)
   end
   v.invalidate