Eliminate Slivers

Purpose

This tool allows to efficiently find and remove sliver polygons.

Description

Sliver polygons are usually small polygons resulting from such overlay operations as Intersect or Union. Sliver polygons normally have area a lot smaller than perimeter. The tool is provided for finding and eliminating such sliver polygons by merging them with neighboring polygons that have the largest area or the longest shared border.

In contrast to the standard Eliminate functionality in ArcGIS the tool does not need the selected features. It finds and processes sliver polygons at once.

Usage

• Select the "Eliminate Slivers" tool from the XTools Pro Analysis Tools.

• Select the input layer potentially containing sliver polygons that you wish to eliminate.

• Specify the name and location of the output feature class.

• Define the slivers selection criteria.

• Select modification for the found slivers.

• Specify ID and Origin fields.

• Press Run to eliminate slivers.

Selection criteria

Slivers can be selected by the shape factor based on one of the following criteria:

• Thinness
  - Thinness ratio shows how close the polygon is to a square (the shape factor is 1 for squares).

• Circularity
  - Circularity ratio shows how close the polygon is to a circle (the shape factor is 1 for circles).

Maximum shape factor must be specified for sliver polygons to be selected:

• Maximum shape factor
  - according to the selected criterion, polygons with specified or smaller shape factor will be considered as slivers. Maximum shape factor value may vary from 0 to 1.

At that, you can specify maximum area value for sliver polygons:

• Maximum sliver area
  - polygons with specified or smaller area will be considered as slivers.

Estimated shape factors (Kt - thinness shape factor, Kc - circularity shape factor):

Sliver modification

Found sliver polygons can be modified one of the following ways:

• Label polygons
  - Sliver polygons will be correspondingly labeled and Origin field with labels will be added to the attribute table of the output feature class.

• Delete slivers
  - Sliver polygons will be deleted from the output feature class.

• Merge slivers by largest area
  - Sliver polygons will be merged with a neighboring polygon with the largest area by dropping the shared border.

• Merge slivers by longest common boundary
  - Sliver polygons will be merged with a neighboring polygon with the longest shared border by dropping the shared border.

 

Output Origin field may have the following labels:

• Intact - the input polygon has been copied to output dataset “as is”.

• Sliver - polygon considered as a sliver (in case the modification “Label polygons” has been selected).

• Merged - the output polygon has been merged with the nearest sliver.

• Updated - the multipart polygon whose parts have been considered as slivers and separated from the input polygon.