multipolygon_type create_multipolygon(const osmium::Area& area) {
size_t num_polygons = 0;
size_t num_rings = 0;
m_impl.multipolygon_start();
for (auto it = area.cbegin(); it != area.cend(); ++it) {
const osmium::OuterRing& ring = static_cast<const osmium::OuterRing&>(*it);
if (it->type() == osmium::item_type::outer_ring) {
if (num_polygons > 0) {
m_impl.multipolygon_polygon_finish();
}
m_impl.multipolygon_polygon_start();
m_impl.multipolygon_outer_ring_start();
add_points(ring);
m_impl.multipolygon_outer_ring_finish();
++num_rings;
++num_polygons;
} else if (it->type() == osmium::item_type::inner_ring) {
m_impl.multipolygon_inner_ring_start();
add_points(ring);
m_impl.multipolygon_inner_ring_finish();
++num_rings;
}
}
// if there are no rings, this area is invalid
if (num_rings == 0) {
throw osmium::geometry_error("invalid area");
}
m_impl.multipolygon_polygon_finish();
return m_impl.multipolygon_finish();
}
void update(const osmium::Area& area) {
update(static_cast<const osmium::OSMObject&>(area));
for (auto it = area.cbegin(); it != area.cend(); ++it) {
if (it->type() == osmium::item_type::outer_ring ||
it->type() == osmium::item_type::inner_ring) {
update(static_cast<const osmium::NodeRefList&>(*it));
}
}
}
osmium_builder_t::wkbs_t
osmium_builder_t::create_polygons(osmium::Area const &area)
{
wkbs_t ret;
try {
size_t num_rings = 0;
for (auto it = area.cbegin(); it != area.cend(); ++it) {
if (it->type() == osmium::item_type::outer_ring) {
auto &ring = static_cast<const osmium::OuterRing &>(*it);
if (num_rings > 0) {
ret.push_back(m_writer.polygon_finish(num_rings));
num_rings = 0;
}
m_writer.polygon_start();
m_writer.polygon_ring_start();
auto num_points = add_mp_points(ring);
m_writer.polygon_ring_finish(num_points);
++num_rings;
} else if (it->type() == osmium::item_type::inner_ring) {
auto &ring = static_cast<const osmium::InnerRing &>(*it);
m_writer.polygon_ring_start();
auto num_points = add_mp_points(ring);
m_writer.polygon_ring_finish(num_points);
++num_rings;
}
}
auto wkb = m_writer.polygon_finish(num_rings);
if (num_rings > 0) {
ret.push_back(wkb);
}
} catch (const osmium::geometry_error &) { /* ignored */
}
return ret;
}