Polygons are divided in tiny strips when exported to EPS, PDF, CGM, or AI Illustrator

Description

When an ArcMap generated EPS, PDF, CGM, or AI Illustrator file is opened in an external editor, like Adobe Illustrator, some large polygons are divided into thin vertical strips.

The Adobe Illustrator export format was not available until ArcGIS 8.1 Service Pack 1.

Cause

This is called polygon dicing, and is implemented on polygons containing more than 20,000 vertices. The purpose is to speed up on-screen drawing and output to a printer.

Workaround

• Simplify the polygon data.
• In ArcGIS 8.1.2 and later, you can use the following Visual Basic code to turn polygon dicing off and on.
  
  Run this code prior to exporting your map:
  
  

  Code:
  Public Sub turnOffDicing()
  
  Dim pGeometryEnv As IGeometryEnvironment3
  Set pGeometryEnv = New GeometryEnvironment
  
  pGeometryEnv.DicingEnabled = False
  
  End Sub
  

  
  
  

  Warning:
  This code will not work with CGM files. Unexpected results can occur when exporting to CGM with polygon dicing turned off. 

  
  To turn polygon dicing back on, run this code:
  
  

  Code:
  Public Sub turnOnDicing()
  
  Dim pGeometryEnv As IGeometryEnvironment3
  Set pGeometryEnv = New GeometryEnvironment
  
  pGeometryEnv.DicingEnabled = True
  
  End Sub 

  
  
  

  Warning:
  Turn polygon dicing back on after exporting, otherwise screen drawing and printing performance may slow considerably.