/* private */
void
ConvexHull::reduce(Coordinate::ConstVect &pts)
{
Coordinate::ConstVect polyPts;
if ( ! computeOctRing(pts, polyPts) ) {
// unable to compute interior polygon for some reason
return;
}
// add points defining polygon
Coordinate::ConstSet reducedSet;
reducedSet.insert(polyPts.begin(), polyPts.end());
/**
* Add all unique points not in the interior poly.
* CGAlgorithms.isPointInRing is not defined for points
* actually on the ring, but this doesn't matter since
* the points of the interior polygon are forced to be
* in the reduced set.
*
* @@TIP: there should be a std::algo for this
*/
for (size_t i=0, n=pts.size(); i<n; ++i)
{
if ( !CGAlgorithms::isPointInRing(*(pts[i]), polyPts) )
{
reducedSet.insert(pts[i]);
}
}
inputPts.assign(reducedSet.begin(), reducedSet.end());
if ( inputPts.size() < 3 ) padArray3(inputPts);
}
/* static */
bool
LineSequencer::isSequenced(const Geometry* geom)
{
const MultiLineString *mls;
if ( nullptr == (mls=dynamic_cast<const MultiLineString *>(geom)) )
{
return true;
}
// the nodes in all subgraphs which have been completely scanned
Coordinate::ConstSet prevSubgraphNodes;
Coordinate::ConstVect currNodes;
const Coordinate* lastNode = nullptr;
for (std::size_t i=0, n=mls->getNumGeometries(); i<n; ++i)
{
const LineString* lineptr = \
dynamic_cast<const LineString*>(mls->getGeometryN(i));
assert(lineptr);
const LineString& line = *lineptr;
const Coordinate* startNode = &(line.getCoordinateN(0));
const Coordinate* endNode = &(line.getCoordinateN(line.getNumPoints() - 1));
/**
* If this linestring is connected to a previous subgraph,
* geom is not sequenced
*/
if (prevSubgraphNodes.find(startNode) != prevSubgraphNodes.end())
{
return false;
}
if (prevSubgraphNodes.find(endNode) != prevSubgraphNodes.end())
{
return false;
}
if (lastNode != nullptr)
{
if (! startNode->equals2D(*lastNode))
{
// start new connected sequence
prevSubgraphNodes.insert(currNodes.begin(),
currNodes.end());
currNodes.clear();
}
}
currNodes.push_back(startNode);
currNodes.push_back(endNode);
lastNode = endNode;
}
return true;
}
/* private */
bool
ConvexHull::computeOctRing(const Coordinate::ConstVect &inputPts,
Coordinate::ConstVect &dest)
{
computeOctPts(inputPts, dest);
// Remove consecutive equal Coordinates
// unique() returns an iterator to the end of the resulting
// sequence, we erase from there to the end.
dest.erase( std::unique(dest.begin(),dest.end()), dest.end() );
// points must all lie in a line
if ( dest.size() < 3 ) return false;
// close ring
dest.push_back(dest[0]);
return true;
}
/*private*/
Coordinate::ConstVect::const_iterator
LineStringSnapper::findSnapForVertex(const Coordinate& pt,
const Coordinate::ConstVect& snapPts)
{
Coordinate::ConstVect::const_iterator end = snapPts.end();
Coordinate::ConstVect::const_iterator candidate = end;
double minDist = snapTolerance;
// TODO: use std::find_if
for ( Coordinate::ConstVect::const_iterator
it=snapPts.begin();
it != end;
++it)
{
assert(*it);
const Coordinate& snapPt = *(*it);
if ( snapPt.equals2D(pt) )
{
#if GEOS_DEBUG
cerr << " points are equal, returning not-found " << endl;
#endif
return end;
}
double dist = snapPt.distance(pt);
#if GEOS_DEBUG
cerr << " distance from snap point " << snapPt << ": " << dist << endl;
#endif
if ( dist < minDist )
{
minDist = dist;
candidate = it;
}
}
#if GEOS_DEBUG
if ( candidate == end ) {
cerr << " no snap point within distance, returning not-found" << endl;
}
#endif
return candidate;
}
/* private */
void
ConvexHull::preSort(Coordinate::ConstVect &pts)
{
// find the lowest point in the set. If two or more points have
// the same minimum y coordinate choose the one with the minimum x.
// This focal point is put in array location pts[0].
for(size_t i=1, n=pts.size(); i<n; ++i)
{
const Coordinate *p0=pts[0]; // this will change
const Coordinate *pi=pts[i];
if ( (pi->y<p0->y) || ((pi->y==p0->y) && (pi->x<p0->x)) )
{
const Coordinate *t=p0;
pts[0]=pi;
pts[i]=t;
}
}
// sort the points radially around the focal point.
std::sort(pts.begin(), pts.end(), RadiallyLessThen(pts[0]));
}