Method processGround

filters/PMFFilter.cpp:219–366

}

void PMFFilter::processGround(PointViewPtr view)
{
    // initialize bounds, rows, columns, and surface
    BOX2D bounds;
    view->calculateBounds(bounds);
    size_t cols = static_cast<size_t>(
        ((bounds.maxx - bounds.minx) / m_args->m_cellSize) + 1);
    size_t rows = static_cast<size_t>(
        ((bounds.maxy - bounds.miny) / m_args->m_cellSize) + 1);

    // initialize surface to NaN
    std::vector<double> ZImin(rows * cols,
                              std::numeric_limits<double>::quiet_NaN());

    // loop through all points, identifying minimum Z value for each populated
    // cell
    for (PointRef p : *view)
    {
        double x = p.getFieldAs<double>(Id::X);
        double y = p.getFieldAs<double>(Id::Y);
        double z = p.getFieldAs<double>(Id::Z);
        int c = static_cast<int>(floor(x - bounds.minx) / m_args->m_cellSize);
        int r = static_cast<int>(floor(y - bounds.miny) / m_args->m_cellSize);
        size_t idx = c * rows + r;
        if (z < ZImin[idx] || std::isnan(ZImin[idx]))
            ZImin[idx] = z;
    }

    // convert vector to PointView for indexing
    PointViewPtr temp = view->makeNew();
    PointId i(0);
    for (size_t c = 0; c < cols; ++c)
    {
        for (size_t r = 0; r < rows; ++r)
        {
            size_t cell = c * rows + r;
            double val = ZImin[cell];
            if (std::isnan(val))
                continue;
            PointRef p = temp->point(i++);
            p.setField(Id::X, bounds.minx + (c + 0.5) * m_args->m_cellSize);
            p.setField(Id::Y, bounds.miny + (r + 0.5) * m_args->m_cellSize);
            p.setField(Id::Z, val);
        }
    }

    // build the 2D KD-tree
    KD2Index& kdi = temp->build2dIndex();

    // loop through all cells, and for each NaN, replace with elevation of
    // nearest neighbor
    std::vector<double> out = ZImin;
    for (size_t c = 0; c < cols; ++c)
    {
        for (size_t r = 0; r < rows; ++r)
        {
            size_t idx = c * rows + r;
            if (!std::isnan(out[idx]))