Open Table of Contents

Eliminate Wizard

Eliminates unwanted polygons (slivers) by merging them into the neighboring polygons or deleting them.

Inputs:

• A polygon feature layer
• Selection method
  • Attribute query - introduces the standard ArcGIS query builder. The user can select the polygons to be eliminated using any query expression
  • Thickness ratio  is expressed as a ratio of the polygon area versus the area of its minimal bounding square. The ratio will have value of 1 for a square. The smaller the value is, the thinner the polygon is. It is a good way of identifying thin polygons (possible slivers).
  • Circularity ratio - for a circle the circularity will be 1. The thinner the polygon is the smaller the circularity will be. This is another way of identifying slivers
• Elimination method
  • Delete - will delete all selected polygons (considered slivers)
  • Join (Largest area) - will join selected polygons with neighboring polygons  that have the largest area
  • Join (Longest boundary) - will join selected polygons with neighboring polygons with the longest common border .
  • Join to the neighbor with the same value in the selected field as the sliver polygon.
  • Identify - will record in the attribute table selected potential slivers. This allows for visual inspection before proceeding with elimination.

Outputs:

• New polygon feature class with selected polygons eliminated or identified as slivers
• New field is added to the attribute table :
  • [ETO_Type]
    • The polygons not affected from elimination will have value - "Original"
    • The slivers that were not eliminated will have value - "Sliver"
    • The polygons that a sliver has been merged to - value - "Changed"

Notes :

• If the source of the original data set is a feature class, to operation can be performed on the original. If the source is a Coverage or Geodatabase, the only option is creating a new feature class
• If the option "Calculate statistics" is selected, the next step will contain valuable statistics - Min, Max and Mean values for the selected method (Thickness ratio or circularity) that will help the user when assigning the ratio to be used for elimination
• Checked "Update Area and Perimeter" option will cause recalculation of the Area and perimeter values. The rest of the original attributes are preserved
• Some of the very tiny slivers can be eliminated with the Clean Polygon Wizard using appropriate value for Fuzzy tolerance, however eliminating larger slivers using this method is not recommended since some unwanted approximation of the polygon shapes might occur.

Examples:

Before Eliminate	Eliminated with Largest Area option	Eliminated with Longest boundary option