Method filter

filters/HagNnFilter.cpp:127–203

void HagNnFilter::filter(PointView& view)
{
    using namespace pdal::Dimension;

    PointViewPtr gView = view.makeNew();
    PointViewPtr ngView = view.makeNew();

    // Separate into ground and non-ground views.
    for (PointId i = 0; i < view.size(); ++i)
    {
        if (view.getFieldAs<uint8_t>(Id::Classification, i) ==
            m_class)
        {
            view.setField(Id::HeightAboveGround, i, 0);
            gView->appendPoint(view, i);
        }
        else
            ngView->appendPoint(view, i);
    }
    BOX2D gBounds;
    gView->calculateBounds(gBounds);

    // Bail if there weren't any points classified as ground.
    if (gView->size() == 0) {
        log()->get(LogLevel::Error) << "Input PointView does not have "
            "any points classified as ground.\n";
        return;
    }

    // Build the 2D KD-tree.
    const KD2Index& kdi = gView->build2dIndex();

    double maxDistance2 = std::pow(m_maxDistance, 2.0);
    // Find Z difference between non-ground points and the nearest
    // neighbor (2D) in the ground view or between non-ground points and the
    // locally-computed surface.
    for (PointId i = 0; i < ngView->size(); ++i)
    {
        PointRef point = ngView->point(i);

        // Non-ground view point for which we're trying to calc HAG
        double x0 = point.getFieldAs<double>(Id::X);
        double y0 = point.getFieldAs<double>(Id::Y);
        double z0 = point.getFieldAs<double>(Id::Z);

        PointIdList ids(m_count);
        std::vector<double> sqr_dists(m_count);
        kdi.knnSearch(x0, y0, m_count, &ids, &sqr_dists);

        // Closest ground point.
        double x = gView->getFieldAs<double>(Id::X, ids[0]);
        double y = gView->getFieldAs<double>(Id::Y, ids[0]);
        double z = gView->getFieldAs<double>(Id::Z, ids[0]);

        double z1;
        // If the close ground point is at the same X/Y as the non-ground
        // point, we're done.  Also, if there's only one ground point, we
        // just use that.