Coordinate LengthIndexedLine::extractPoint(double index, double offsetDistance) const
{
LinearLocation loc = LengthLocationMap::getLocation(linearGeom, index);
Coordinate ret;
loc.getSegment(linearGeom)->pointAlongOffset(loc.getSegmentFraction(), offsetDistance, ret);
return ret;
}
/* public static */
LinearLocation
LinearLocation::getEndLocation(const Geometry* linear)
{
// assert: linear is LineString or MultiLineString
LinearLocation loc;
loc.setToEnd(linear);
return loc;
}
LinearIterator::LinearIterator(const Geometry* linear, const LinearLocation& start):
vertexIndex(segmentEndVertexIndex(start)),
componentIndex(start.getComponentIndex()),
linear(linear),
numLines(static_cast<unsigned int>(linear->getNumGeometries()))
{
loadCurrentLine();
}
/* private */
LinearLocation
LengthLocationMap::resolveHigher(const LinearLocation& loc) const
{
if (! loc.isEndpoint(*linearGeom)) return loc;
unsigned int compIndex = loc.getComponentIndex();
// if last component can't resolve any higher
if (compIndex >= linearGeom->getNumGeometries() - 1) return loc;
do {
compIndex++;
} while (compIndex < linearGeom->getNumGeometries() - 1
&& linearGeom->getGeometryN(compIndex)->getLength() == 0);
// resolve to next higher location
return LinearLocation(compIndex, 0, 0.0);
}
double LengthLocationMap::getLength(const LinearLocation& loc) const
{
double totalLength = 0.0;
LinearIterator it(linearGeom);
while (it.hasNext())
{
if (! it.isEndOfLine())
{
Coordinate p0 = it.getSegmentStart();
Coordinate p1 = it.getSegmentEnd();
double segLen = p1.distance(p0);
// length falls in this segment
if (loc.getComponentIndex() == it.getComponentIndex()
&& loc.getSegmentIndex() == it.getVertexIndex())
{
return totalLength + segLen * loc.getSegmentFraction();
}
totalLength += segLen;
}
it.next();
}
return totalLength;
}
unsigned int LinearIterator::segmentEndVertexIndex(const LinearLocation& loc)
{
if (loc.getSegmentFraction() > 0.0)
return loc.getSegmentIndex() + 1;
return loc.getSegmentIndex();
}
Coordinate LengthIndexedLine::extractPoint(double index) const
{
LinearLocation loc = LengthLocationMap::getLocation(linearGeom, index);
Coordinate coord = loc.getCoordinate(linearGeom);
return coord;
}