Syntax

   FACTORY_DEF <ReaderKeyword> SliverRemovingFactory
   [FACTORY_NAME <factory name>]
   [INPUT FEATURE_TYPE <factory type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*
   [GROUP_BY [<attribute name>]+]
   [FLUSH_WHEN_GROUPS_CHANGE (Yes|No)]
   [ALGORITHM_VERSION (1|2)]
   [REPAIR (AbsoluteMajority|LongestBoundary|Random|
            NumberOfNeighbors|PriorityAttribute|AggressivePriority)]
   [PRIORITY_ATTR <numeric attribute>]
   [CLEANING_TOLERANCE (AUTO|<tolerance>)]
   [FILL_LARGE_GAPS (yes|no)]
   [DEAGGREGATE_INPUT (yes|no)]
   [CONNECT_Z_MODE (EXTEND|AVERAGE|FIRST_WINS|LAST_WINS|IGNORE_Z)]
   [MISSING_VAL_MODE (REMOVE_NANS|FLAG_NANS|COMPUTE_NANS|<sentinelVal>)]
   [COMPUTE_MEASURES_MODE (CONTINUOUS|DISCRETE)]
   [OUTPUT (REPAIRED|INVALID|REJECTED|REMNANTS) * FEATURE_TYPE <feature type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*

Overview

   Removes gaps and overlaps between areas in 2D by creating a planar partition
   using all input areas, then assigning each region to exactly one of the inputs
   features.
   
   If GROUP_BY is specified, only features with similar attribute values specified
   by the GROUP_BY clause will interact with each other.

   If the GROUP_BY clause is specified, and FLUSH_WHEN_GROUPS_CHANGE is set to Yes, 
   the factory will flush the current group whenever a feature from a different 
   group is encountered.
   
   This factory originally supported two algorithms for creating planar partition and
   resolving conflicts. Support for ALGORITHM_VERSION 1 has been removed. 
   ALGORITHM_VERSION 2 is now used in all cases, and the description of ALGORITHM_VERSION 1 
   is left for reference.

   ALGORITHM_VERSION 1

      This algorithm creates a planar partition by triangulating the input
      areas. All sealed gaps and all overlapping regions will be assigned
      to one of the adjacent polygons.

      The REPAIR flag determines how ties are broken when assigning tags to each
      triangle. In longest boundary, for each region sharing the same set of tags,
      the tag belonging to the longest boundary will be used. For random mode, each
      contiguous region will be assigned randomly to a neighboring polygon. In the
      priority attribute modes, the value of PRIORITY_ATTR will determine the
      winner. Zero is considered highest priority. In regular priority attribute
      mode, the higher priority polygon will be assigned overlaps, and the lowest
      priority polygon will be assigned gaps. This preserves the boundary of the
      higher priority polygon. In aggressive priority mode, the higher priority
      polygon is assigned both gaps and overlaps.

   ALGORITHM_VERSION 2

      This algorithm creates a planar partition by overlaying the input areas.
      
      The area overlay will merge geometries within CLEANING_TOLERANCE. If the
      CLEANING_TOLERANCE keyword does not exist or has the value "AUTO", a 
      cleaning tolerance will automatically be generated based on the input
      geometries.

      If FILL_ALL_GAPS is true, all sealed gaps in the coverage will be filled.
      If FILL_ALL_GAPS is false, only gaps within the CLEANING_TOLERANCE will
      be filled.

      Sealed gaps and overlapping regions greater than the CLEANING_TOLERANCE
      will be filled via the REPAIR options detailed in ALGORITHM_VERSION 1.

Assumptions

   Input features are assumed to have area geometries. Non-area geometries
   and aggregate geometries are not supported by this factory. Additionally,
   all input areas are assumed to be valid areas with no duplicate points,
   and no self-intersections.

Output Tags

   The SliverRemovingFactory supports the following output tags.

   REPAIRED

      Features that have been repaired.

   REMNANTS

      Geometries that were collapsed during repair, or attributes that
      were not matched to any repaired area.

   INVALID
 
      Features containing non-polygon geometries. This output tag was
      previously used when the ALGORITHM_VERSION was unspecified or 1,
      and the REJECT_INVALID_GEOM was unspecified or NO. The REJECTED
      Tag is now used instead.

   REJECTED
 
      Features containing non-polygon geometries with a rejection code.

TO BE RESOLVED

   AbsoluteMajority and NumberOfNeighbors added to Syntax section above as
   REPAIR parameters, but not documented.