mbedward wrote:
>
> I'm not sure if this is relevant to your problem (I haven't used the
> graph code in geotools) but to split your LineStrings at intersections
> you could try the following JTS trick (courtesy of Martin Davis's
> presentation at 2007 FOSS4G conference
>
> Collection lines = ... // your line strings
> Geometry mls = geomFactory.buildGeometry(lines); // create a
> MultiLineString
> Point mlsPt = geomFactory.createPoint(mls.getCoordinate()); // get an
> arbitrary point on a line
> Geometry nodedLines = mls.union(pt); // union the MultiLineString
> with the point
>
> This has the (almost magical) effect of noding all of the line
> intersections.
>
Thanks Michael! Here's the method I built out of your reply:
private List<LineString> splitMLines(Vector<MultiLineString> mlines) {
GeometryFactory geomFactory = new GeometryFactory();
List<LineString> lines = new Vector<LineString>();
int imax = mlines.size();
for (int i = 0; i < imax; ++i) {
MultiLineString mls = mlines.get(i);
for (int j = 0;j <= mls.getNumGeometries()-1;j++) {
// get an arbitrary point on a line
Point mlsPt =
geomFactory.createPoint(mls.getCoordinate());
// union the MultiLineString with the point
Geometry nodedLines = mls.union(mlsPt);
if (nodedLines instanceof MultiLineString) {
for (int z = 0;z <=
mls.getNumGeometries()-1;z++) {
LineString ls = (LineString)
mls.getGeometryN(z);
lines.add(ls);
}
}
else if (nodedLines instanceof LineString){
lines.add((LineString) nodedLines);
}
else System.out.println("Error! Type is: " +
nodedLines.getGeometryType());
}
}
return lines;
}
But it gives me 167 partitions and that way the graph that is not well
connected. Did I do something wrong?
--
View this message in context:
http://n2.nabble.com/Building-a-connected-graph-with-OSM-data---Splitting-LineStrings-at-their-intersections-tp3086758p3131785.html
Sent from the geotools-gt2-users mailing list archive at Nabble.com.
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