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Use DouglasPeucker with squaredEuclideanDistance

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This commit is contained in:
Patrick Niklaus
2016-04-09 00:39:20 +02:00
parent 67834def5f
commit 4886d46d91
3 changed files with 116 additions and 56 deletions
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src/engine/douglas_peucker.cpp
+29 -2
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@@ -16,6 +16,31 @@ namespace osrm
namespace engine
{
struct FastPerpendicularDistance
{
FastPerpendicularDistance(const util::Coordinate start, const util::Coordinate target)
: projected_start(util::coordinate_calculation::mercator::fromWGS84(start)),
projected_target(util::coordinate_calculation::mercator::fromWGS84(target))
{
}
// Normed to the thresholds table
std::uint64_t operator()(const util::Coordinate coordinate) const
{
auto projected = util::coordinate_calculation::mercator::fromWGS84(coordinate);
util::FloatCoordinate projected_point_on_segment;
std::tie(std::ignore, projected_point_on_segment) =
util::coordinate_calculation::projectPointOnSegment(projected_start, projected_target,
projected);
auto squared_distance = util::coordinate_calculation::squaredEuclideanDistance(projected,
projected_point_on_segment);
return squared_distance;
}
const util::FloatCoordinate projected_start;
const util::FloatCoordinate projected_target;
};
std::vector<util::Coordinate> douglasPeucker(std::vector<util::Coordinate>::const_iterator begin,
std::vector<util::Coordinate>::const_iterator end,
const unsigned zoom_level)
@@ -51,14 +76,16 @@ std::vector<util::Coordinate> douglasPeucker(std::vector<util::Coordinate>::cons
BOOST_ASSERT_MSG(pair.second < size, "right border outside of geometry");
BOOST_ASSERT_MSG(pair.first <= pair.second, "left border on the wrong side");
double max_distance = 0;
std::uint64_t max_distance = 0;
auto farthest_entry_index = pair.second;
FastPerpendicularDistance perpendicular_distance(begin[pair.first], begin[pair.second]);
// sweep over range to find the maximum
for (auto idx = pair.first + 1; idx != pair.second; ++idx)
{
using namespace util::coordinate_calculation;
const auto distance = perpendicularDistance(begin[pair.first], begin[pair.second], begin[idx]);
const auto distance = perpendicular_distance(begin[idx]);
// found new feasible maximum?
if (distance > max_distance &&
distance > detail::DOUGLAS_PEUCKER_THRESHOLDS[zoom_level])