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Added SrtmTileManager::GetBilinearHeight.

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Signed-off-by: Viktor Govako <viktor.govako@gmail.com>
This commit is contained in:
Viktor Govako
2023-02-23 18:55:07 -03:00
committed by Konstantin Pastbin
parent ac50520ca8
commit 767f27e00a
7 changed files with 59 additions and 29 deletions
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2
generator/altitude_generator.cpp
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@@ -37,7 +37,7 @@ public:
// AltitudeGetter overrides:
Altitude GetAltitude(m2::PointD const & p) override
{
return m_srtmManager.GetTriangleHeight(mercator::ToLatLon(p));
return m_srtmManager.GetAltitude(mercator::ToLatLon(p));
}
void PrintStatsAndPurge() override

2
generator/feature_segments_checker/feature_segments_checker.cpp
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@@ -188,7 +188,7 @@ public:
for (uint32_t i = 0; i < numPoints; ++i)
{
// Feature segment altitude.
geometry::Altitude altitude = m_srtmManager.GetTriangleHeight(mercator::ToLatLon(f.GetPoint(i)));
geometry::Altitude altitude = m_srtmManager.GetAltitude(mercator::ToLatLon(f.GetPoint(i)));
pointAltitudes[i] = altitude == geometry::kInvalidAltitude ? 0 : altitude;
if (i == 0)
{

14
generator/generator_tests/srtm_parser_test.cpp
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@@ -87,21 +87,23 @@ UNIT_TEST(SRTM_TileTest)
double const len = 1.0 / (sz - 1);
TEST_EQUAL(tile.GetHeight({0, 0}), 4, ());
TEST_EQUAL(tile.GetTriangleHeight({0, 0}), 4, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetTriangleHeight({0, 0}), 4.0, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetBilinearHeight({0, 0}), 4.0, ());
TEST_EQUAL(tile.GetHeight({len, len}), 2, ());
TEST_EQUAL(tile.GetTriangleHeight({len, len}), 2, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetTriangleHeight({len, len}), 2.0, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetBilinearHeight({len, len}), 2.0, ());
// Key difference here: GetHeight snaps on the nearest node, while GetTriangleHeight calculates
// from the nearest nodes' triangle.
double l = len / 2;
Altitude h = tile.GetHeight({l, l});
TEST(h == 4 || h == 2, (h));
TEST_EQUAL(tile.GetTriangleHeight({l, l}), 3, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetTriangleHeight({l, l}), 3.0, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetBilinearHeight({l, l}), 3.0, ());
l = 3 * len + len / 2;
h = tile.GetHeight({l, l});
TEST(h == -4 || h == -2, (h));
TEST_EQUAL(tile.GetTriangleHeight({l, l}), -3, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetTriangleHeight({l, l}), -3.0, ());
TEST_ALMOST_EQUAL_ULPS(tile.GetBilinearHeight({l, l}), -3.0, ());
}
/*

17
generator/srtm_coverage_checker/srtm_coverage_checker.cpp
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@@ -48,10 +48,10 @@ public:
return (routing::IsRoad(types) && !types.Has(m_ferry));
}
geometry::Altitude GetHeight(ms::LatLon const & coord)
geometry::Altitude GetAltitude(ms::LatLon const & coord)
{
std::lock_guard guard(m_mutex);
return m_manager.GetTriangleHeight(coord);
return m_manager.GetAltitude(coord);
}
void Purge()
@@ -119,7 +119,7 @@ void CheckCoverage(SafeTileManager & manager)
for (size_t i = 0; i < ft.GetPointsCount(); ++i)
{
auto const height = manager.GetHeight(mercator::ToLatLon(ft.GetPoint(i)));
auto const height = manager.GetAltitude(mercator::ToLatLon(ft.GetPoint(i)));
if (height != geometry::kInvalidAltitude)
good++;
}
@@ -150,9 +150,9 @@ void CheckDistance(SafeTileManager & manager)
for (size_t i = 1; i < ft.GetPointsCount(); ++i)
{
auto const ll1 = mercator::ToLatLon(ft.GetPoint(i-1));
auto const alt1 = manager.GetHeight(ll1);
auto const alt1 = manager.GetAltitude(ll1);
auto const ll2 = mercator::ToLatLon(ft.GetPoint(i));
auto const alt2 = manager.GetHeight(ll2);
auto const alt2 = manager.GetAltitude(ll2);
if (alt1 == geometry::kInvalidAltitude || alt2 == geometry::kInvalidAltitude)
{
@@ -171,7 +171,7 @@ void CheckDistance(SafeTileManager & manager)
ms::LatLon const ll(ll2.m_lat * a + ll1.m_lat * (1 - a), ll2.m_lon * a + ll1.m_lon * (1 - a));
// Get diff between approx altitude and real one.
auto const alt = manager.GetHeight(ll);
auto const alt = manager.GetAltitude(ll);
if (alt == geometry::kInvalidAltitude)
{
LOG_SHORT(LWARNING, ("Invalid altitude for the middle point:", ll));
@@ -242,7 +242,10 @@ int main(int argc, char * argv[])
}
else
{
cout << "H = " << manager.GetHeight({lat, lon}) << "; TrgH = " << manager.GetTriangleHeight({lat, lon});
auto const & tile = manager.GetTile({lat, lon});
cout << "H = " << tile.GetHeight({lat, lon}) <<
"; Trg = " << tile.GetTriangleHeight({lat, lon}) <<
"; Bilinear = " << tile.GetBilinearHeight({lat, lon});
cout << endl;
}
}

31
generator/srtm_parser.cpp
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@@ -135,7 +135,7 @@ geometry::Altitude SrtmTile::GetHeightRC(size_t row, size_t col) const
return ReverseByteOrder(Data()[ix]);
}
geometry::Altitude SrtmTile::GetTriangleHeight(ms::LatLon const & coord) const
double SrtmTile::GetTriangleHeight(ms::LatLon const & coord) const
{
if (!IsValid())
return geometry::kInvalidAltitude;
@@ -179,9 +179,32 @@ geometry::Altitude SrtmTile::GetTriangleHeight(ms::LatLon const & coord) const
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 static_cast<geometry::Altitude>(std::round(a1 * GetHeightRC(p1.y, p1.x) +
a2 * GetHeightRC(p2.y, p2.x) +
a3 * GetHeightRC(p3.y, p3.x)));
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

20
generator/srtm_parser.hpp
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@@ -30,8 +30,15 @@ public:
/// @{
/// Nearest serialized height.
geometry::Altitude GetHeight(ms::LatLon const & coord) const;
/// Height from underlying triangle (better than GetHeight).
geometry::Altitude GetTriangleHeight(ms::LatLon const & coord) const;
/// Triangle interpolation.
double GetTriangleHeight(ms::LatLon const & coord) const;
/// Bilinear interpolation.
double GetBilinearHeight(ms::LatLon const & coord) const;
geometry::Altitude GetAltitude(ms::LatLon const & coord) const
{
return static_cast<geometry::Altitude>(std::round(GetBilinearHeight(coord)));
}
/// @}
using LatLonKey = std::pair<int32_t, int32_t>;
@@ -68,14 +75,9 @@ public:
SrtmTile const & GetTile(ms::LatLon const & coord);
geometry::Altitude GetHeight(ms::LatLon const & coord)
geometry::Altitude GetAltitude(ms::LatLon const & coord)
{
return GetTile(coord).GetHeight(coord);
}
geometry::Altitude GetTriangleHeight(ms::LatLon const & coord)
{
return GetTile(coord).GetTriangleHeight(coord);
return GetTile(coord).GetAltitude(coord);
}
size_t GeTilesNumber() const { return m_tiles.size(); }

2
topography_generator/generator.cpp
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@@ -184,7 +184,7 @@ public:
, m_bottomLat(bottomLat)
{}
/// @todo Should we use the same approach as in SrtmTile::GetTriangleHeight?
/// @todo Should we use the same approach as in SrtmTile::GetTriangleHeight/GetBilinearHeight?
/// This function is used in ASTER fiter only.
Altitude GetValue(ms::LatLon const & pos) override
{