Class SimpleSnapRounder
java.lang.Object
org.locationtech.jts.noding.snapround.SimpleSnapRounder
- All Implemented Interfaces:
Noder
Uses Snap Rounding to compute a rounded,
fully noded arrangement from a set of
SegmentString
s.
Implements the Snap Rounding technique described in
the papers by Hobby, Guibas & Marimont, and Goodrich et al.
Snap Rounding assumes that all vertices lie on a uniform grid;
hence the precision model of the input must be fixed precision,
and all the input vertices must be rounded to that precision.
This implementation uses simple iteration over the line segments. This is not the most efficient approach for large sets of segments.
This implementation appears to be fully robust using an integer precision model. It will function with non-integer precision models, but the results are not 100% guaranteed to be correctly noded.
- Version:
- 1.7
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate LineIntersector
private Collection
private final PrecisionModel
private final double
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate void
checkCorrectness
(Collection inputSegmentStrings) void
computeNodes
(Collection inputSegmentStrings) Computes the noding for a collection ofSegmentString
s.private void
computeSnaps
(Collection segStrings, Collection snapPts) Computes nodes introduced as a result of snapping segments to snap points (hot pixels)private void
computeSnaps
(NodedSegmentString ss, Collection snapPts) void
computeVertexSnaps
(Collection edges) Computes nodes introduced as a result of snapping segments to vertices of other segmentsprivate void
Performs a brute-force comparison of every segment in eachSegmentString
.private List
findInteriorIntersections
(Collection segStrings, LineIntersector li) Computes all interior intersections in the collection ofSegmentString
s, and returns theirCoordinate
s.Returns aCollection
of fully nodedSegmentString
s.private void
snapRound
(Collection segStrings, LineIntersector li)
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Field Details
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pm
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li
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scaleFactor
private final double scaleFactor -
nodedSegStrings
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Constructor Details
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SimpleSnapRounder
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Method Details
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getNodedSubstrings
Description copied from interface:Noder
Returns aCollection
of fully nodedSegmentString
s. The SegmentStrings have the same context as their parent.- Specified by:
getNodedSubstrings
in interfaceNoder
- Returns:
- a Collection of NodedSegmentStrings representing the substrings
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computeNodes
Description copied from interface:Noder
Computes the noding for a collection ofSegmentString
s. Some Noders may add all these nodes to the input SegmentStrings; others may only add some or none at all.- Specified by:
computeNodes
in interfaceNoder
- Parameters:
inputSegmentStrings
- a Collection of NodedSegmentStrings
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checkCorrectness
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snapRound
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findInteriorIntersections
Computes all interior intersections in the collection ofSegmentString
s, and returns theirCoordinate
s. Does NOT node the segStrings.- Returns:
- a list of Coordinates for the intersections
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computeSnaps
Computes nodes introduced as a result of snapping segments to snap points (hot pixels)- Parameters:
li
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computeSnaps
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computeVertexSnaps
Computes nodes introduced as a result of snapping segments to vertices of other segments- Parameters:
edges
- the list of segment strings to snap together
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computeVertexSnaps
Performs a brute-force comparison of every segment in eachSegmentString
. This has n^2 performance.
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