组合一系列 LineString

Question

我有一个 LineString 序列，例如 lineString1 和 lineString2

其中 lineString1.getEndPoint() == lineString2.getStartPoint() 或 lineString1.getStartPoint() == lineString2.getEndPoint() 我想获得 LineString 对象（不是 MultiLineString），它将由 lineString1 和 lineString2.

组合而成

我没有找到任何好的解决方案。

Answer 1

正在关注 geotool documentation：

GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
LineString combinedLineString = GeometryFactory.createLineString(
    lineString1.getControlPoints()
        .addAll(lineString2.getControlPoints())
    );

Answer 2

您可以使用 union method of GeometryCollection to join the LineStrings. See the documentation here - 对于线串的集合，它具有完全节点和溶解线条的效果。

static Geometry combineIntoOneGeometry( Collection<Geometry> geometryCollection ){
     GeometryFactory factory = FactoryFinder.getGeometryFactory( null );

     // note the following geometry collection may be invalid (say with overlapping polygons)
     GeometryCollection geometryCollection =
          (GeometryCollection) factory.buildGeometry( geometryCollection );

     return geometryCollection.union();
 }

Answer 3

您需要使用 JTS LineMerger 来实现这一点，它 returns 一个 Collection<LineString> 但在您的示例中，这是一行，因为它们连接（在其他情况下只有一些线条可能会接触）。

import java.util.Collection;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.io.ParseException;
import com.vividsolutions.jts.io.WKTReader;
import com.vividsolutions.jts.operation.linemerge.LineMerger;

public class LineJoin {

  public static void main(String[] args) throws ParseException {
    /*String[] WKTS = { "LINESTRING (254058.76074485347 475001.2186020431, 255351.04293761664 474966.9279243938)",
        "LINESTRING (255351.04293761664 474966.9279243938, 255529.29662365236 474272.4599921228)",
        "LINESTRING (255529.29662365236 474272.4599921228, 256166.05830998957 473979.44920198264)",
        "LINESTRING (256166.05830998957 473979.44920198264, 256082.8878282134 472762.2531920295)",
        "LINESTRING (256082.8878282134 472762.2531920295, 254245.37250651795 472802.681197444)",
        "LINESTRING (254245.37250651795 472802.681197444, 254294.87550167093 473782.10435392085)",
        "LINESTRING (255802.5570897992 475306.663459122, 256973.3861333156 473826.71649389854)",
        "LINESTRING (256973.3861333156 473826.71649389854, 256996.781511873 472271.0759416939)",
        "LINESTRING (254134.08645022905 471750.25133671844, 253091.20265363617 473772.75685744354)",
        "LINESTRING (252764.19811300343 475015.97340571403, 253526.90397945273 476194.3201198712)",
        "LINESTRING (253526.90397945273 476194.3201198712, 254983.29259833007 475930.5996061625)" };*/
    String[] WKTS = {"LINESTRING(10 40,11 41)","LINESTRING(11 41,12 42)"};
    WKTReader reader = new WKTReader();
    LineMerger merger = new LineMerger();
    for (String wkt : WKTS) {
      Geometry geom = reader.read(wkt);
      merger.add(geom);
    }

    Collection<LineString> collection = merger.getMergedLineStrings();

    for (LineString l : collection) {
      System.out.println(l);
    }
  }

}

对于您的测试输入，它给出：

LINESTRING (10 40, 11 41, 12 42)

对于注释掉的 WKT，您将得到：

LINESTRING (252764.19811300343 475015.97340571403, 253526.90397945273 476194.3201198712, 254983.29259833007 475930.5996061625)
LINESTRING (254134.08645022905 471750.25133671844, 253091.20265363617 473772.75685744354)
LINESTRING (254058.76074485347 475001.2186020431, 255351.04293761664 474966.9279243938, 255529.29662365236 474272.4599921228, 256166.05830998957 473979.44920198264, 256082.8878282134 472762.2531920295, 254245.37250651795 472802.681197444, 254294.87550167093 473782.10435392085)
LINESTRING (255802.5570897992 475306.663459122, 256973.3861333156 473826.71649389854, 256996.781511873 472271.0759416939)

组合一系列 LineString

Combine a sequence of LineString

java

gis

geotools