Jts个人学习笔记-gohui - 图文

Jts个人学习笔记

Jts（Java Topology Suite）是关于GIS空间数据Java的API。

目录

三角网的创建 ............................................................................................................................................................... 2 1、创建Delaunay三角网： .................................................................................................................................................. 2 2、创建Conforming Delaunay三角网 .................................................................................................................................. 2 3、创建Voronoi图 ................................................................................................................................................................ 3 4、Quad-Edge，四方边缘结构 ............................................................................................................................................. 3 5、在Tin、DTin、Voronoi中插入一点（IncrementalDelaunayTriangulator）................................................................ 11 DistanceOp类的相关操作：com.vividsolutions.jts.operation.distance ........................................................................ 11 1、nearestPoints(Geometry g0, Geometry g1) .................................................................................................................... 11 2、distance(Geometry g0, Geometry g1) ............................................................................................................................. 12 3、nearestLocations() ........................................................................................................................................................... 12 LineSegment类的相关操作：com.vividsolutions.jts.geom .......................................................................................... 12 1、closestPoint(Coordinate p) .............................................................................................................................................. 12 2、closestPoints(LineSegment p) .......................................................................................................................................... 13 3、distance (Coordinate p)和distancePerpendicular(Coordinate p) ................................................................................... 13 4、intersection(LineSegment line)和lineIntersection(LineSegment line) ........................................................................... 13 5、pointAlong(double slf) ..................................................................................................................................................... 14 6、pointAlongOffset(double slf, double od) ......................................................................................................................... 14 7、project(Coordinate p)和project(LineSegment seg) ........................................................................................................ 15 8、projectionFactor(Coordinate p) ....................................................................................................................................... 15 9、segmentFraction(Coordinate inputPt) ............................................................................................................................. 16 CGAlgorithms类的相关操作：com.vividsolutions.jts.algorithm .................................................................................. 16 1、orientationIndex(Coordinate p1, Coordinate p2, Coordinate q) ..................................................................................... 16 Angle类的相关操作：com.vividsolutions.jts.algorithm ............................................................................................... 16 1、angleBetween(Coordinate tip1, Coordinate tail, Coordinate tip2) ................................................................................. 17 2、angleBetweenOriented(Coordinate tip1, Coordinate tail, Coordinate tip2) ................................................................... 17 AffineTransformationFactory类的操作：com.vividsolutions.jts.geom.util ................................................................... 17 1、createFromBaseLines(Coordinate src0, Coordinate src1, Coordinate dest0, Coordinate dest1) ................................... 18 AffineTransformation类的操作：com.vividsolutions.jts.geom.util .............................................................................. 18 1、构造函数：AffineTransformation(double[] matrix) ....................................................................................................... 18

三角网的创建

Jts中创建Tin时，会自己添加新的点，不是太好（ArcGIS在创建Tin时也是会自己新建点的）

1、创建Delaunay三角网：

DelaunayTriangulationBuilder delaunayBuilder = new DelaunayTriangulationBuilder(); delaunayBuilder.setSites(coorList);

Geometry geo = delaunayBuilder.getEdges(new GeometryFactory());

2、创建Conforming Delaunay三角网

ConformingDelaunayTriangulationBuilder conformTriBuilder = new ConformingDelaunayTriangulationBuilder();

conformTriBuilder.setSites(geoFactory.createMultiPoint(coorList.toArray(new Coordinate[0])));

conformTriBuilder.setConstraints(geoFactory.createMultiLineString(lineStrings)); Geometry geo = delaunayBuilder.getEdges(new GeometryFactory());

注：还有一个ConformingDelaunayTriangulator，这个类里面包含了更多的方法。但是我们在创建的时候不用管这个类，直接用ConformingDelaunayTriangulationBuilder就好，因为在

ConformingDelaunayTriangulationBuilder内部，它自己调用了ConformingDelaunayTriangulator。真正的Tin创建工作，都是交给ConformingDelaunayTriangulator的，

ConformingDelaunayTriangulationBuilder给我们提供了一个更方便的接口。

ConformingDelaunayTriangulationBuilder部分源码：

3、创建Voronoi图

VoronoiDiagramBuilder voronoiBuilder = new VoronoiDiagramBuilder(); voronoiBuilder.setSites(coorList);

Geometry geo = voronoiBuilder.getDiagram(new GeometryFactory());

4、Quad-Edge，四方边缘结构

在所有的类中（DelaunayTriangulationBuilder、ConformingDelaunayTriangulationBuilder、VoronoiDiagramBuilder），都有一个getSubdivision()方法， DTin CDTin Voronoi 它们都返回一个QuadEdgeSubdivision类的对象， 其结构如下： O：Orig D：Dest L：Left R：Right

Next：左边的面 Prev：右边的面

System.out.println(\ + q);

System.out.println(\ + q.dNext()); System.out.println(\ + q.dPrev()); System.out.println(\ + q.lNext()); System.out.println(\ + q.lPrev()); System.out.println(\ + q.rNext()); System.out.println(\ + q.rPrev()); System.out.println(\ + q.oNext()); System.out.println(\ + q.oPrev()); System.out.println(\ + q.dest()); System.out.println(\ + q.orig());

System.out.println(\ + q.rot());//有错，toString里面的错 System.out.println(\ + q.invRot());//有错，toString里面的错

System.out.println(\ + q.sym());