Function ProcessVectorZonesByChunk

alg/zonal.cpp:1338–2046

#ifndef HAVE_GEOS
    bool ProcessVectorZonesByChunk(GDALProgressFunc, void *)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "The GEOS library is required to iterate over blocks of the "
                 "input rasters. Processing can be performed by iterating over "
                 "the input features instead.");
        return false;
#else
    bool ProcessVectorZonesByChunk(GDALProgressFunc pfnProgress,
                                   void *pProgressData)
    {
        if (!Init())
        {
            return false;
        }

        std::unique_ptr<GDALDataset> poAlignedWeightsDS;
        // Align the weighting dataset to the values.
        if (m_weights)
        {
            bool resampled = false;
            poAlignedWeightsDS = GetVRT(*m_weights, m_src, resampled);
            if (!poAlignedWeightsDS)
            {
                return false;
            }
            if (resampled)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Resampled weights to match source raster using "
                         "average resampling.");
            }
        }

        auto TreeDeleter = [this](GEOSSTRtree *tree)
        { GEOSSTRtree_destroy_r(m_geosContext, tree); };

        std::unique_ptr<GEOSSTRtree, decltype(TreeDeleter)> tree(
            GEOSSTRtree_create_r(m_geosContext, 10), TreeDeleter);

        std::vector<std::unique_ptr<OGRFeature>> features;
        std::map<int, std::vector<gdal::RasterStats<double>>> statsMap;

        // Construct spatial index of all input features, storing the index
        // of the feature.
        {
            OGREnvelope oGeomExtent;
            for (auto &poFeatureIn : *std::get<OGRLayer *>(m_zones))
            {
                features.emplace_back(poFeatureIn.release());

                const OGRGeometry *poGeom = features.back()->GetGeometryRef();

                if (poGeom == nullptr || poGeom->IsEmpty())
                {
                    continue;
                }