Example of "cleaning" a line network using JSTS to create a properly noded segment network (i.e. nodes at every intersection between segments).

testNoder.js

var jsts = require("jsts"),
    fs = require("fs"),
    javascript = require("javascript.util"),
    assert = require("assert"),
    lines = [
        "LINESTRING(-110.5 32.1,-110.45 32.2,-110.4 32.1)",
        "LINESTRING(-110.5 32.25,-110.45 32.2,-110.45 32.15,-110.4 32.25)"
    ],
    expected = [
        "LINESTRING(-110.5 32.1,-110.45 32.2)",
        "LINESTRING(-110.45 32.2,-110.4375 32.175)",
        "LINESTRING(-110.4375 32.175,-110.4 32.1)",
        "LINESTRING(-110.5 32.25,-110.45 32.2)",
        "LINESTRING(-110.45 32.2,-110.45 32.15,-110.4375 32.175)",
        "LINESTRING(-110.4375 32.175,-110.4 32.25)"
    ],
    calculated = [];

var reader = new jsts.io.WKTReader(),
    writer = new jsts.io.WKTWriter(),
    noder = new jsts.noding.MCIndexNoder(),
    intersector = new jsts.noding.IntersectionAdder(new jsts.algorithm.RobustLineIntersector()),
    factory = new jsts.geom.GeometryFactory(),
    segments = new javascript.util.ArrayList();

// Convert the WKT Lines into jsts NodedSegmentStrings
lines.forEach(function (line) {
    var feature = reader.read(line);
    segments.add(new jsts.noding.NodedSegmentString(feature.points));
});

// Clean the network of lines
noder.setSegmentIntersector(intersector);
noder.computeNodes(segments);
var cleanedSegments = noder.getNodedSubstrings();

// Extract jsts LineStrings from the cleaned segments
var i = cleanedSegments.iterator();
while (i.hasNext()) {
    var segment = i.next(),
        coords = segment.getCoordinates(),
        line = factory.createLineString(coords);
    calculated.push(writer.write(line));    
}

// Check that it worked
assert.equal(expected.length, calculated.length, "The noder did not produce the expected number of line segments");
expected.forEach(function (expectedLine) {
    assert(calculated.indexOf(expectedLine) !== -1, "The noder did not produce the expected line segment: " + expectedLine);
});

Hi,

I tried to get JSTS to clean some lines with your script. It seems there is a problem. I'm using JSTS in browser, but i get a problem at noder.setSegmentIntersector(intersector)
I get this error:
Uncaught TypeError: inputSegStrings.iterator is not a function

Have there been any changes or can you tell me why this might not work anymore?

//Anders