double LengthIndexOfPoint::indexOfFromStart(const Coordinate& inputPt, double minIndex) const
{
double minDistance = numeric_limits<double>::max();
double ptMeasure = minIndex;
double segmentStartMeasure = 0.0;
LineSegment seg;
LinearIterator it(linearGeom);
while (it.hasNext())
{
if (! it.isEndOfLine())
{
seg.p0 = it.getSegmentStart();
seg.p1 = it.getSegmentEnd();
double segDistance = seg.distance(inputPt);
double segMeasureToPt = segmentNearestMeasure(&seg, inputPt, segmentStartMeasure);
if (segDistance < minDistance
&& segMeasureToPt > minIndex)
{
ptMeasure = segMeasureToPt;
minDistance = segDistance;
}
segmentStartMeasure += seg.getLength();
}
it.next();
}
return ptMeasure;
}
WayLocation LocationOfPoint::locate(const Coordinate& inputPt) const
{
double minDistance = std::numeric_limits<double>().max();
int minIndex = 0;
double minFrac = -1.0;
LineSegment seg;
if (_length == -1)
{
_length = ElementConverter(_map).convertToLineString(_way)->getLength();
}
if (_length <= 0.0)
{
return WayLocation(_map, _way, 0, 0);
}
for (size_t i = 0; i < _way->getNodeCount() - 1; i++) {
seg.p0 = _map->getNode(_way->getNodeId(i))->toCoordinate();
seg.p1 = _map->getNode(_way->getNodeId(i + 1))->toCoordinate();
double segDistance = seg.distance(inputPt);
double segFrac = segmentFraction(seg, inputPt);
if (segDistance < minDistance) {
minIndex = i;
minFrac = segFrac;
minDistance = segDistance;
}
}
return WayLocation(_map, _way, minIndex, minFrac);
}
WayLocation LocationOfPoint::locateAfter(const Coordinate& inputPt, const WayLocation& minLocation)
const
{
if (minLocation.isValid() == false)
{
return locate(inputPt);
}
assert(minLocation.getWay() == _way);
double minDistance = std::numeric_limits<double>().max();
WayLocation nextClosestLocation = minLocation;
LineSegment seg;
size_t startIndex = 0;
startIndex = (size_t)minLocation.getSegmentIndex();
for (size_t i = startIndex; i < _way->getNodeCount() - 1; i++)
{
seg.p0 = _map->getNode(_way->getNodeId(i))->toCoordinate();
seg.p1 = _map->getNode(_way->getNodeId(i + 1))->toCoordinate();
if (i == startIndex)
{
seg.p0 = minLocation.getCoordinate();
}
double segDistance = seg.distance(inputPt);
double segFrac = segmentFraction(seg, inputPt);
if (segDistance < minDistance)
{
// if this is the first case (a partial line segment)
if (i == startIndex)
{
// recalculate the segFrac in terms of the whole line segment.
segFrac = minLocation.getSegmentFraction() +
(1 - minLocation.getSegmentFraction()) * segFrac;
}
nextClosestLocation = WayLocation(_map, _way, i, segFrac);
minDistance = segDistance;
}
}
// Return the minDistanceLocation found.
// This will not be null, since it was initialized to minLocation
Assert::isFalse(nextClosestLocation >= minLocation,
"computed location is before specified minimum location");
return nextClosestLocation;
}
/* NOTE: this is called findSegmentIndexToSnap in JTS */
CoordinateList::iterator
LineStringSnapper::findSegmentToSnap(
const Coordinate& snapPt,
CoordinateList::iterator from,
CoordinateList::iterator too_far)
{
LineSegment seg;
double minDist = snapTolerance; // make sure the first closer then
// snapTolerance is accepted
CoordinateList::iterator match=too_far;
// TODO: use std::find_if
for ( ; from != too_far; ++from)
{
seg.p0 = *from;
CoordinateList::iterator to = from;
++to;
seg.p1 = *to;
#if GEOS_DEBUG
cerr << " Checking segment " << seg << endl;
#endif
/**
* Check if the snap pt is equal to one of
* the segment endpoints.
*
* If the snap pt is already in the src list,
* don't snap at all (unless allowSnappingToSourceVertices
* is set to true)
*/
if ( seg.p0.equals2D(snapPt) || seg.p1.equals2D(snapPt) )
{
if (allowSnappingToSourceVertices) {
#if GEOS_DEBUG
cerr << " snap point matches a segment endpoint, checking next segment"
<< endl;
#endif
continue;
} else {
#if GEOS_DEBUG
cerr << " snap point matches a segment endpoint, giving up seek" << endl;
#endif
return too_far;
}
}
double dist = seg.distance(snapPt);
if ( dist >= minDist) {
#if GEOS_DEBUG
cerr << " snap point distance " << dist
<< " not smaller than tolerance "
<< snapTolerance << " or previous closest "
<< minDist << endl;
#endif
continue;
}
#if GEOS_DEBUG
cerr << " snap point distance " << dist << " within tolerance "
<< snapTolerance << " and closer than previous candidate "
<< minDist << endl;
#endif
if ( dist == 0.0 ) return from; // can't find any closer
match = from;
minDist = dist;
}
return match;
}
