ARCVIEW 3.0 BUFFER BUTTON

Buffer selected features.  This routine is a rewrite of the sample
script "buffer.ave", included with AV3.0 -- this rewrite saves the
resulting buffer to a shapefile.

=======================================================================

INSTALLING THE BUFFER BUTTON IN THE DEFAULT PROJECT

Note:  this script is not in the default.apr maintained at my Web page.

1) Begin a NEW ArcView 3.0 session.

2) Create a new script by double-clicking on the "Scripts" icon

3) Use "Properties..." under the "Script" menu to rename Script1 to
   View.Buffer

4) Paste the following text:

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

'View.Buffer
'Buffers selected features to new theme

TheView=av.getactivedoc
theTheme=theView.getactivethemes.get(0)
TheType=TheTheme.GetSrcName.getsubname
theftab=theTheme.getftab
thebitmap=theftab.getselection
theShape=theFtab.findfield("Shape")

'**** get buffer distance

thedisplay=theview.getdisplay
theunits=thedisplay.getunits

if (thebitmap.count<1) then exit
end

'Test if the Map Units have been set uses Distance units if they are set,
'otherwise uses distance units
if (theunits=#UNITS_LINEAR_UNKNOWN) then
 msgbox.warning("Sorry no map units defined.  Please define the map units in the View, Properties dialog.","Warning")
 exit
end
check=TRUE


Distunits=TheDisplay.GetDistanceUnits

if (distunits = #UNITS_LINEAR_UNKNOWN) then
  distunits=theunits
  check=FALSE
end

theunitname=distunits.asstring.astokens("_").get(2).lcase
anum=(MsgBox.Input("Enter the buffer distance in "+theunitname+".","Buffer","100"))

if (anum=NIL) then exit end
abuffernum=anum.asnumber

if (check=TRUE) then
   answer=Units.Convert(abuffernum, Distunits, TheUnits)
   abuffernum=answer
end

'**** get output file

out_name = av.GetProject.MakeFileName("theme", "shp")
out_name = FileDialog.Put(out_name, "*.shp", "Output Shapefile")
if (out_name = nil) then
   exit
end
PShape = FTab.MakeNew(out_name,Polygon)
fields = List.Make
fields.Add(Field.Make("id",#FIELD_LONG,11,0))
PShape.AddFields(fields)

'**** create buffer shape list

av.showmsg("Buffering...")
count=0
BuffList=List.Make
for each x in theBitmap
   count=count+1
   progress = (count/thebitmap.count) * 100
   doMore = av.SetStatus( progress )
   av.usewaitcursor
   anewshape=theftab.returnvalue(theshape, x)
      if (theview.getprojection<>"") then
         newshape=anewshape.returnprojected(theview.getprojection)
      else
         newshape=anewshape
      end
   abufferdist=abuffernum
   if (theview.getprojection<>"") then
      tmpbuffshp=newshape.returnbuffered(abufferdist)
      thebuffshp=tmpbuffshp.returnunprojected(theview.getprojection)
   else
      thebuffshp=newshape.returnbuffered(abufferdist)
   end
   BuffList.Add(thebuffshp)
end

'**** dissolve buffer shapes and write to FTab

av.showmsg("Dissolving...")
count=0
thewhole = BuffList.Get(0)
for each ashape in BuffList
  count=count+1
  progress = (count/BuffList.count) * 100
  doMore = av.SetStatus( progress )
  av.usewaitcursor
  thing1=ashape
  thewhole1=thewhole.returnunion(thing1)
  thewhole=thewhole1
end

theID = 1
recno = PShape.AddRecord
PShape.SetValue(PShape.FindField("id"),recno,theID)
PShape.SetValue(PShape.FindField("shape"),recno,thewhole)

'**** add buffer theme to a view

if (MsgBox.YesNo("Add shapefile as theme to a view?",
  "Buffer Theme", true).Not) then
  exit
end

viewList = {}
for each d in av.GetProject.GetDocs
  if (d.Is(View)) then
    viewList.Add( d )
  end
end

addToView = MsgBox.ListAsString( viewList,"Add Theme to:", "Buffer Theme" )

if (addToView <> nil) then

  if (addToView = "<New View>") then
    addToView = View.Make
    addToView.GetWin.Open
  end

  mergeTheme = FTheme.Make( PShape )
  addToView.AddTheme( mergeTheme )

  ' Bring the View to the front...
  addToView.GetWin.Activate
end

av.clearmsg

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

5) Create a new script, named View.Buffer.Update, with the following
text:

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

'View.Buffer.Update

if (av.getactivedoc.getactivethemes.Count > 0) then
   Self.SetEnabled(
   (av.getactivedoc.getactivethemes.get(0).getftab.getselection.count > 0)
   and
   (av.getactivedoc.getdisplay.getunits <> #UNITS_LINEAR_UNKNOWN)
   )
else
   Self.SetEnabled(false)
end

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

6) Compile and close both scripts

7) Double-click the tool bar, choose "View" and "Buttons", and create a
new button

8) Double-click "Click" and select View.Buffer

9) Double-click "Update" and select View.Buffer.Update

10) Double-click "Help" and enter:
    Buffer//Buffer Selected Features

11) Double-click "Icon" and select SelectBuffer

12) Click the "Make Default Button" and then close the Customize dialog
    box

13) EXIT ArcView (do not save changes to "Untitled") and you're done!

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INSTALLING THE BUTTON IN A SPECIFIC PROJECT

1) Open the desired project and follow steps 2-11 above

2) Close the "Customizer" and save the project

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USING THE BUFFER BUTTON

1) The view's map units must be defined.

2) Make the desired theme active.

3) Select the features to be buffered.

4) Click the buffer button.

5) Enter the buffer distance.

6) Specify the output shapefile.

7) You will be asked if you want to add the shapefile to a view; if so,
you will be asked to specify which one.


=======================================================================

Mark Cederholm
plp@pierssen.com
http://www.pierssen.com/PC/arcinfo.htm
http://www.pierssen.com/arcview/arcview.htm