int OGRCircularString::IsFullCircle( double& cx, double& cy,
double& square_R ) const
{
if( getNumPoints() == 3 && get_IsClosed() )
{
const double x0 = getX(0);
const double y0 = getY(0);
const double x1 = getX(1);
const double y1 = getY(1);
cx = (x0 + x1) / 2;
cy = (y0 + y1) / 2;
square_R = (x1 - cx) * (x1 - cx) + (y1 - cy) * (y1 - cy);
return TRUE;
}
// Full circle defined by 2 arcs?
else if( getNumPoints() == 5 && get_IsClosed() )
{
double R_1 = 0.0;
double cx_1 = 0.0;
double cy_1 = 0.0;
double alpha0_1 = 0.0;
double alpha1_1 = 0.0;
double alpha2_1 = 0.0;
double R_2 = 0.0;
double cx_2 = 0.0;
double cy_2 = 0.0;
double alpha0_2 = 0.0;
double alpha1_2 = 0.0;
double alpha2_2 = 0.0;
if( OGRGeometryFactory::GetCurveParmeters(
getX(0), getY(0),
getX(1), getY(1),
getX(2), getY(2),
R_1, cx_1, cy_1, alpha0_1, alpha1_1, alpha2_1) &&
OGRGeometryFactory::GetCurveParmeters(
getX(2), getY(2),
getX(3), getY(3),
getX(4), getY(4),
R_2, cx_2, cy_2, alpha0_2, alpha1_2, alpha2_2) &&
fabs(R_1-R_2) < 1e-10 &&
fabs(cx_1-cx_2) < 1e-10 &&
fabs(cy_1-cy_2) < 1e-10 &&
(alpha2_1 - alpha0_1) * (alpha2_2 - alpha0_2) > 0 )
{
cx = cx_1;
cy = cy_1;
square_R = R_1 * R_1;
return TRUE;
}
}
return FALSE;
}
double OGRCircularString::get_Area() const
{
if( IsEmpty() || !get_IsClosed() )
return 0;
double cx = 0.0;
double cy = 0.0;
double square_R = 0.0;
if( IsFullCircle(cx, cy, square_R) )
{
return M_PI * square_R;
}
// Optimization for convex rings.
if( IsConvex() )
{
// Compute area of shape without the circular segments.
double dfArea = get_LinearArea();
// Add the area of the spherical segments.
dfArea += get_AreaOfCurveSegments();
return dfArea;
}
OGRLineString* poLS = CurveToLine();
const double dfArea = poLS->get_Area();
delete poLS;
return dfArea;
}
double OGRCompoundCurve::get_Area() const
{
if( IsEmpty() || !get_IsClosed() )
return 0;
// Optimization for convex rings.
if( IsConvex() )
{
// Compute area of shape without the circular segments.
OGRPointIterator* poIter = getPointIterator();
OGRLineString oLS;
oLS.setNumPoints( getNumPoints() );
OGRPoint p;
for( int i = 0; poIter->getNextPoint(&p); i++ )
{
oLS.setPoint( i, p.getX(), p.getY() );
}
double dfArea = oLS.get_Area();
delete poIter;
// Add the area of the spherical segments.
dfArea += get_AreaOfCurveSegments();
return dfArea;
}
OGRLineString* poLS = CurveToLine();
double dfArea = poLS->get_Area();
delete poLS;
return dfArea;
}
OGRErr OGRLinearRing::transform( OGRCoordinateTransformation *poCT )
{
const bool bIsClosed = getNumPoints() > 2 && CPL_TO_BOOL(get_IsClosed());
OGRErr eErr = OGRLineString::transform(poCT);
if( bIsClosed && eErr == OGRERR_NONE && !get_IsClosed() )
{
CPLDebug("OGR", "Linearring is not closed after coordinate "
"transformation. Forcing last point to be identical to "
"first one");
// Force last point to be identical to first point.
// This is a safety belt in case the reprojection of the same coordinate
// isn't perfectly stable. This can for example happen in very rare cases
// when reprojecting a cutline with a RPC transform with a DEM that
// is a VRT whose sources are resampled...
OGRPoint oStartPoint;
StartPoint( &oStartPoint );
setPoint( getNumPoints()-1, &oStartPoint);
}
return eErr;
}
