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module;
#include <boost/geometry.hpp>
#include <boost/geometry/srs/epsg.hpp>
#include <boost/geometry/srs/transformation.hpp>
export module routemon:geo.multizonal;
import std;
import :geo;
import :geo.utm;
import :geo.utm.zone_local;
import :geo.wgs84;
namespace routemon::geo::multizonal {
template<std::default_initializable T>
class multi_zone
{
std::array<T, utm::zone::max().as_index() + 1> zones_;
public:
auto operator[](utm::zone z) -> T&
{
return zones_[z.as_index()];
}
auto operator[](utm::zone z) const -> T const&
{
return zones_[z.as_index()];
}
};
namespace wgs84
{
// Transformations from WGS 84 (EPSG:4326)
using transform_from_t = bgeo::srs::transformation<bgeo::srs::static_epsg<4326>>;
class utm_transform : public transform_from_t
{
utm::zone to_zone_;
public:
explicit utm_transform(utm::zone to_zone)
: transform_from_t{{}, bgeo::srs::epsg{to_zone.wgs84_proj_epsg()}},
to_zone_{to_zone}
{
}
utm_transform()
: utm_transform{utm::zone::min()}
{}
auto apply(utm::zonable_wgs84_point p) -> utm::zone_local::point
{
auto local_p = utm::zone_local::point{to_zone_, 0.0, 0.0};
forward(p, local_p);
return local_p;
}
};
class utm_transforms : public multi_zone<utm_transform>
{
utm_transforms()
{
for (auto z = utm::zone::min(); z != utm::zone::max(); z = z.next())
{
(*this)[z] = utm_transform{z};
}
}
public:
static utm_transforms const& instance()
{
static utm_transforms inst;
return inst;
}
};
auto neighbor_utm_zone(utm::zonable_wgs84_point p) -> std::pair<utm::zone, double>
{
auto separating_meridian_lon = std::round(p.lon() / 6.0) * 6.0;
auto closest_zone_middle = separating_meridian_lon < p.lon()
? separating_meridian_lon - 3.0
: separating_meridian_lon + 3.0;
auto closest_zone = utm::zone::for_wgs84_point(utm::zonable_wgs84_point::from(geo::wgs84::normalized_point{geo::wgs84::from_lat_lon(p.lat(), closest_zone_middle)}).value());
auto separating_meridian_ls = geo::wgs84::linestring{
geo::wgs84::from_lat_lon(90.0, 0.0),
geo::wgs84::from_lat_lon(0.0, separating_meridian_lon),
geo::wgs84::from_lat_lon(-90.0, 0.0),
};
auto closest_zone_dist = bgeo::distance(p, separating_meridian_ls, geo::wgs84::vincenty_strategy{});
return std::make_pair(closest_zone, closest_zone_dist);
}
} // namespace wgs84
struct multizone_linestring
{
multi_zone<std::vector<utm::zone_local::prim::linestring>> segments;
// TODO: consider taking an input range instead
explicit multizone_linestring(utm::zonable_wgs84_linestring const& ls)
{
auto to_utm = wgs84::utm_transforms::instance();
auto working = multi_zone<utm::zone_local::prim::linestring>{};
auto mprev_p_zone = std::optional<utm::zone>{};
auto mprev_p_alt_zone = std::optional<utm::zone>{};
auto push = [&](utm::zonable_wgs84_point p, utm::zone z)
{ working[z].push_back(to_utm[z].apply(p)); };
auto flush = [&](utm::zone z)
{
segments[z].push_back(std::move(working[z]));
working[z] = {};
};
for (auto const& p : ls)
{
auto p_zone = utm::zone::for_wgs84_point(p);
auto mp_alt_zone = std::optional<utm::zone>{};
if (auto [neighbor_zone, neighbor_zone_dist] = wgs84::neighbor_utm_zone(p);
neighbor_zone_dist < 30.0 /* m */)
mp_alt_zone = neighbor_zone;
assert(!mp_alt_zone || *mp_alt_zone != p_zone);
push(p, p_zone);
if (mp_alt_zone)
push(p, *mp_alt_zone);
if (mprev_p_zone && *mprev_p_zone != p_zone && mprev_p_zone != mp_alt_zone)
{
push(p, *mprev_p_zone);
flush(*mprev_p_zone);
}
if (mprev_p_alt_zone && *mprev_p_alt_zone != p_zone && mprev_p_alt_zone != mp_alt_zone)
{
push(p, *mprev_p_alt_zone);
flush(*mprev_p_alt_zone);
}
mprev_p_zone = p_zone;
mprev_p_alt_zone = mp_alt_zone;
}
if (mprev_p_zone && !working[*mprev_p_zone].empty())
{
flush(*mprev_p_zone);
}
if (mprev_p_alt_zone && !working[*mprev_p_alt_zone].empty())
{
flush(*mprev_p_alt_zone);
}
}
};
struct zoned_linestring_seg_seq
{
std::vector<utm::zone_local::linestring> segments;
explicit zoned_linestring_seg_seq(utm::zonable_wgs84_linestring ls)
{
auto to_utm = wgs84::utm_transforms::instance();
auto mworking_seg = std::optional<utm::zone_local::linestring>{};
for (auto const& p : ls)
{
auto p_zone = utm::zone::for_wgs84_point(p);
if (mworking_seg && mworking_seg->zone != p_zone)
{
mworking_seg->push_back(to_utm[mworking_seg->zone].apply(p));
segments.push_back(std::move(*mworking_seg));
mworking_seg = std::nullopt;
}
if (!mworking_seg)
mworking_seg = utm::zone_local::linestring{p_zone};
mworking_seg->push_back(to_utm[p_zone].apply(p));
}
if (mworking_seg && !mworking_seg->empty())
{
segments.push_back(std::move(*mworking_seg));
}
}
};
template<class T>
class linestring_rtree
{
public:
using index_value = std::tuple<utm::zone_local::prim::box, utm::zone_local::prim::linestring, T>;
private:
multi_zone<bgeo::index::rtree<index_value, bgeo::index::quadratic<16>>> local_rtrees_;
public:
template<std::convertible_to<T> U>
auto insert(utm::zonable_wgs84_linestring const& ls, U&& arg) -> void
{
auto zone_segments = multizone_linestring{ls}.segments;
for (auto z = utm::zone::min(); z != utm::zone::max(); z = z.next())
{
for (auto ls : zone_segments[z])
{
utm::zone_local::prim::box blse =
bgeo::return_buffer<utm::zone_local::prim::box>(bgeo::return_envelope<utm::zone_local::prim::box>(ls), 30.0 /* m */);
local_rtrees_[z].insert(index_value{blse, std::move(ls), std::forward<U>(arg)});
}
}
}
auto size() const -> std::size_t
{
auto total_size = 0uz;
for (auto z = utm::zone::min(); z != utm::zone::max(); z = z.next())
total_size += local_rtrees_[z].size();
return total_size;
}
// Note: the same T may be generated more than once!
auto intersection(zoned_linestring_seg_seq const& lss) const -> std::generator<T const&>
{
for (auto const& ls : lss.segments)
{
// auto ls_box = bgeo::return_envelope<utm::zone_local::prim::box>(ls);
for (auto it = local_rtrees_[ls.zone].qbegin(bgeo::index::intersects(ls));
it != local_rtrees_[ls.zone].qend(); it++)
{
if (bgeo::intersects(ls, std::get<1>(*it)))
{
co_yield std::get<2>(*it);
}
}
}
}
};
} // namespace routemon::geo::multizonal
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