Function CutGeometryOnDateLineAndAddToMulti

ogr/ogrgeometryfactory.cpp:3367–3536

/************************************************************************/

static void CutGeometryOnDateLineAndAddToMulti(OGRGeometryCollection *poMulti,
                                               const OGRGeometry *poGeom,
                                               double dfDateLineOffset)
{
    const OGRwkbGeometryType eGeomType = wkbFlatten(poGeom->getGeometryType());
    switch (eGeomType)
    {
        case wkbPoint:
        {
            auto poPoint = poGeom->toPoint()->clone();
            WrapPointDateLine(poPoint);
            poMulti->addGeometryDirectly(poPoint);
            break;
        }

        case wkbPolygon:
        case wkbLineString:
        {
            bool bSplitLineStringAtDateline = false;
            OGREnvelope oEnvelope;

            poGeom->getEnvelope(&oEnvelope);
            const bool bAroundMinus180 = (oEnvelope.MinX < -180.0);

            // Naive heuristics... Place to improve.
#ifdef HAVE_GEOS
            std::unique_ptr<OGRGeometry> poDupGeom;
            bool bWrapDateline = false;
#endif

            const double dfLeftBorderX = 180 - dfDateLineOffset;
            const double dfRightBorderX = -180 + dfDateLineOffset;
            const double dfDiffSpace = 360 - dfDateLineOffset;

            const double dfXOffset = (bAroundMinus180) ? 360.0 : 0.0;
            if (oEnvelope.MinX < -180 || oEnvelope.MaxX > 180 ||
                (oEnvelope.MinX + dfXOffset > dfLeftBorderX &&
                 oEnvelope.MaxX + dfXOffset > 180))
            {
#ifndef HAVE_GEOS
                CPLError(CE_Failure, CPLE_NotSupported,
                         "GEOS support not enabled.");
#else
                bWrapDateline = true;
#endif
            }
            else
            {
                auto poLS = eGeomType == wkbPolygon
                                ? poGeom->toPolygon()->getExteriorRing()
                                : poGeom->toLineString();
                if (poLS)
                {
                    double dfMaxSmallDiffLong = 0;
                    bool bHasBigDiff = false;
                    // Detect big gaps in longitude.
                    for (int i = 1; i < poLS->getNumPoints(); i++)
                    {