/*private*/
void
LineIntersector::intersection(const Coordinate& p1,
const Coordinate& p2, const Coordinate& q1, const Coordinate& q2,
Coordinate &intPt) const
{
intersectionWithNormalization(p1, p2, q1, q2, intPt);
/*
* Due to rounding it can happen that the computed intersection is
* outside the envelopes of the input segments. Clearly this
* is inconsistent.
* This code checks this condition and forces a more reasonable answer
*
* MD - May 4 2005 - This is still a problem. Here is a failure case:
*
* LINESTRING (2089426.5233462777 1180182.3877339689,
* 2085646.6891757075 1195618.7333999649)
* LINESTRING (1889281.8148903656 1997547.0560044837,
* 2259977.3672235999 483675.17050843034)
* int point = (2097408.2633752143,1144595.8008114607)
*/
if (! isInSegmentEnvelopes(intPt))
{
intPt = CentralEndpointIntersector::getIntersection(p1, p2, q1, q2);
#if GEOS_DEBUG
cerr << "Intersection outside segment envelopes, snapped to "
<< intPt.toString() << endl;
#endif
}
if (precisionModel!=NULL) {
precisionModel->makePrecise(intPt);
}
#if COMPUTE_Z
double ztot = 0;
double zvals = 0;
double zp = interpolateZ(intPt, p1, p2);
double zq = interpolateZ(intPt, q1, q2);
if ( !ISNAN(zp)) { ztot += zp; zvals++; }
if ( !ISNAN(zq)) { ztot += zq; zvals++; }
if ( zvals ) intPt.z = ztot/zvals;
#endif // COMPUTE_Z
}
Coordinate*
RobustLineIntersector::intersection(const Coordinate& p1,const Coordinate& p2,const Coordinate& q1,const Coordinate& q2) const
{
Coordinate n1=p1;
Coordinate n2=p2;
Coordinate n3=q1;
Coordinate n4=q2;
Coordinate normPt;
//normalize(&n1, &n2, &n3, &n4, &normPt);
normalizeToEnvCentre(n1, n2, n3, n4, normPt);
Coordinate *intPt=NULL;
#if DEBUG
cerr<<"RobustIntersector::intersection(p1,p2,q1,q2) called:"<<endl;
cerr<<" p1"<<p1.toString()<<endl;
cerr<<" p2"<<p2.toString()<<endl;
cerr<<" q1"<<q1.toString()<<endl;
cerr<<" q2"<<q2.toString()<<endl;
cerr<<" n1"<<n1.toString()<<endl;
cerr<<" n2"<<n2.toString()<<endl;
cerr<<" n3"<<n3.toString()<<endl;
cerr<<" n4"<<n4.toString()<<endl;
#endif
try {
intPt=HCoordinate::intersection(n1,n2,n3,n4);
#if DEBUG
cerr<<" HCoordinate found intersection h:"<<h->toString()<<endl;
#endif
} catch (const NotRepresentableException& e) {
delete intPt;
Assert::shouldNeverReachHere("Coordinate for intersection is not calculable"+e.toString());
}
intPt->x+=normPt.x;
intPt->y+=normPt.y;
/**
*
* MD - May 4 2005 - This is still a problem. Here is a failure case:
*
* LINESTRING (2089426.5233462777 1180182.3877339689,
* 2085646.6891757075 1195618.7333999649)
* LINESTRING (1889281.8148903656 1997547.0560044837,
* 2259977.3672235999 483675.17050843034)
* int point = (2097408.2633752143,1144595.8008114607)
*/
#if DEBUG
if (! isInSegmentEnvelopes(intPt))
{
cerr<<"Intersection outside segment envelopes: "<<
intPt->toString();
}
#endif
if (precisionModel!=NULL) precisionModel->makePrecise(intPt);
#if COMPUTE_Z
double ztot = 0;
double zvals = 0;
double zp = interpolateZ(*intPt, p1, p2);
double zq = interpolateZ(*intPt, q1, q2);
if ( !ISNAN(zp)) { ztot += zp; zvals++; }
if ( !ISNAN(zq)) { ztot += zq; zvals++; }
if ( zvals ) intPt->z = ztot/zvals;
#endif // COMPUTE_Z
return intPt;
}
