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Fr4nz D13trich 2025-11-22 13:58:55 +01:00
parent 4af19165ec
commit 68073add76
12458 changed files with 12350765 additions and 2 deletions

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generator/srtm_parser.cpp Normal file
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#include "generator/srtm_parser.hpp"
#include "platform/platform.hpp"
#include "coding/endianness.hpp"
#include "coding/zip_reader.hpp"
#include "base/file_name_utils.hpp"
#include "base/logging.hpp"
#include <cmath>
#include <fstream>
#include <iomanip>
#include <sstream>
namespace generator
{
namespace
{
int constexpr kArcSecondsInDegree = 60 * 60;
size_t constexpr kSrtmTileSize = (kArcSecondsInDegree + 1) * (kArcSecondsInDegree + 1) * 2;
struct UnzipMemDelegate : public ZipFileReader::Delegate
{
explicit UnzipMemDelegate(std::vector<uint8_t> & buffer) : m_buffer(buffer), m_completed(false)
{
m_buffer.reserve(kSrtmTileSize);
}
// ZipFileReader::Delegate overrides:
void OnBlockUnzipped(size_t size, char const * data) override { m_buffer.insert(m_buffer.end(), data, data + size); }
void OnStarted() override
{
m_buffer.clear();
m_completed = false;
}
void OnCompleted() override { m_completed = true; }
std::vector<uint8_t> & m_buffer;
bool m_completed;
};
std::string GetSrtmContFileName(std::string const & dir, std::string const & base)
{
return base::JoinPath(dir, base + ".SRTMGL1.hgt.zip");
}
} // namespace
// SrtmTile ----------------------------------------------------------------------------------------
SrtmTile::SrtmTile(SrtmTile && rhs) : m_data(std::move(rhs.m_data)), m_valid(rhs.m_valid)
{
rhs.Invalidate();
}
void SrtmTile::Init(std::string const & dir, ms::LatLon const & coord)
{
Invalidate();
std::string const base = GetBase(coord);
std::string const cont = GetSrtmContFileName(dir, base);
std::string file = base + ".hgt";
// Original files are stored in zip archives. Alternatively, they can be loaded
// from uncompressed files like "N34E012.hgt".
static bool const loadFromZip = static_cast<bool>(std::ifstream(cont));
if (loadFromZip)
{
UnzipMemDelegate delegate(m_data);
try
{
ZipFileReader::UnzipFile(cont, file, delegate);
}
catch (ZipFileReader::LocateZipException const &)
{
// Sometimes packed file has different name. See N39E051 measure.
file = base + ".SRTMGL1.hgt";
ZipFileReader::UnzipFile(cont, file, delegate);
}
if (!delegate.m_completed)
{
LOG(LWARNING, ("Can't decompress SRTM file:", cont));
Invalidate();
return;
}
}
else
{
m_data = base::ReadFile(base::JoinPath(dir, file));
}
if (m_data.size() != kSrtmTileSize)
{
LOG(LWARNING, ("Bad decompressed SRTM file size:", cont, m_data.size()));
Invalidate();
return;
}
m_valid = true;
}
// static
ms::LatLon SrtmTile::GetCoordInSeconds(ms::LatLon const & coord)
{
double ln = coord.m_lon - static_cast<int>(coord.m_lon);
if (ln < 0)
ln += 1;
double lt = coord.m_lat - static_cast<int>(coord.m_lat);
if (lt < 0)
lt += 1;
lt = 1 - lt; // from North to South
return {kArcSecondsInDegree * lt, kArcSecondsInDegree * ln};
}
geometry::Altitude SrtmTile::GetHeight(ms::LatLon const & coord) const
{
if (!IsValid())
return geometry::kInvalidAltitude;
auto const ll = GetCoordInSeconds(coord);
return GetHeightRC(std::lround(ll.m_lat), std::lround(ll.m_lon));
}
geometry::Altitude SrtmTile::GetHeightRC(size_t row, size_t col) const
{
size_t const ix = row * (kArcSecondsInDegree + 1) + col;
CHECK_LESS(ix, Size(), (row, col));
return ReverseByteOrder(Data()[ix]);
}
double SrtmTile::GetTriangleHeight(ms::LatLon const & coord) const
{
if (!IsValid())
return geometry::kInvalidAltitude;
auto const ll = GetCoordInSeconds(coord);
m2::Point<int> const p1(std::lround(ll.m_lon), std::lround(ll.m_lat));
auto p2 = p1;
if (p2.x > ll.m_lon)
{
if (p2.x > 0)
--p2.x;
}
else if (p2.x < ll.m_lon)
{
if (p2.x < kArcSecondsInDegree)
++p2.x;
}
auto p3 = p1;
if (p3.y > ll.m_lat)
{
if (p3.y > 0)
--p3.y;
}
else if (p3.y < ll.m_lat)
{
if (p3.y < kArcSecondsInDegree)
++p3.y;
}
// Approximate height from triangle p1, p2, p3.
// p1.y == p2.y; p1.x == p3.x
// https://stackoverflow.com/questions/36090269/finding-height-of-point-on-height-map-triangles
int const det = (p2.y - p3.y) * (p1.x - p3.x) + (p3.x - p2.x) * (p1.y - p3.y);
if (det == 0)
return GetHeightRC(p1.y, p1.x);
double const a1 = ((p2.y - p3.y) * (ll.m_lon - p3.x) + (p3.x - p2.x) * (ll.m_lat - p3.y)) / det;
double const a2 = ((p3.y - p1.y) * (ll.m_lon - p3.x) + (p1.x - p3.x) * (ll.m_lat - p3.y)) / det;
double const a3 = 1 - a1 - a2;
return a1 * GetHeightRC(p1.y, p1.x) + a2 * GetHeightRC(p2.y, p2.x) + a3 * GetHeightRC(p3.y, p3.x);
}
double SrtmTile::GetBilinearHeight(ms::LatLon const & coord) const
{
if (!IsValid())
return geometry::kInvalidAltitude;
auto const ll = GetCoordInSeconds(coord);
m2::Point<int> const p1(static_cast<int>(ll.m_lon), static_cast<int>(ll.m_lat));
auto p2 = p1;
if (p2.x < kArcSecondsInDegree)
++p2.x;
if (p2.y < kArcSecondsInDegree)
++p2.y;
// https://en.wikipedia.org/wiki/Bilinear_interpolation
double const denom = (p2.x - p1.x) * (p2.y - p1.y);
if (denom == 0)
return GetHeightRC(p1.y, p1.x);
return (GetHeightRC(p1.y, p1.x) * (p2.x - ll.m_lon) * (p2.y - ll.m_lat) +
GetHeightRC(p1.y, p2.x) * (ll.m_lon - p1.x) * (p2.y - ll.m_lat) +
GetHeightRC(p2.y, p1.x) * (p2.x - ll.m_lon) * (ll.m_lat - p1.y) +
GetHeightRC(p2.y, p2.x) * (ll.m_lon - p1.x) * (ll.m_lat - p1.y)) /
denom;
}
// static
std::string SrtmTile::GetPath(std::string const & dir, std::string const & base)
{
return GetSrtmContFileName(dir, base);
}
// static
SrtmTile::LatLonKey SrtmTile::GetKey(ms::LatLon const & coord)
{
ms::LatLon center{floor(coord.m_lat) + 0.5, floor(coord.m_lon) + 0.5};
if (coord.m_lat < 0)
center.m_lat -= 1.0;
if (coord.m_lon < 0)
center.m_lon -= 1.0;
return {static_cast<int32_t>(center.m_lat), static_cast<int32_t>(center.m_lon)};
}
// static
std::string SrtmTile::GetBase(ms::LatLon const & coord)
{
auto key = GetKey(coord);
std::ostringstream ss;
if (coord.m_lat < 0)
{
ss << "S";
key.first = -key.first;
}
else
ss << "N";
ss << std::setw(2) << std::setfill('0') << key.first;
if (coord.m_lon < 0)
{
ss << "W";
key.second = -key.second;
}
else
ss << "E";
ss << std::setw(3) << key.second;
return ss.str();
}
geometry::Altitude * SrtmTile::DataForTests(size_t & sz)
{
m_valid = true;
sz = kArcSecondsInDegree + 1;
m_data.resize(kSrtmTileSize, 0);
return reinterpret_cast<geometry::Altitude *>(m_data.data());
}
void SrtmTile::Invalidate()
{
m_data.clear();
m_data.shrink_to_fit();
m_valid = false;
}
// SrtmTileManager ---------------------------------------------------------------------------------
SrtmTile const & SrtmTileManager::GetTile(ms::LatLon const & coord)
{
auto res = m_tiles.emplace(SrtmTile::GetKey(coord), SrtmTile());
if (res.second)
{
try
{
res.first->second.Init(m_dir, coord);
}
catch (RootException const & e)
{
std::string const base = SrtmTile::GetBase(coord);
LOG(LINFO, ("Can't init SRTM tile:", base, "reason:", e.Msg()));
}
}
return res.first->second;
}
void SrtmTileManager::Purge()
{
MapT().swap(m_tiles);
}
} // namespace generator