nearest_points.cuh File Reference

#include <rmm/cuda_stream_view.hpp>
#include <cuspatial/detail/point_linestring_nearest_points.cuh>

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Functions
template<class Vec2dItA , class Vec2dItB , class OffsetIteratorA , class OffsetIteratorB , class OffsetIteratorC , class OutputIt >
OutputIt	cuspatial::pairwise_point_linestring_nearest_points (OffsetIteratorA points_geometry_offsets_first, OffsetIteratorA points_geometry_offsets_last, Vec2dItA points_first, Vec2dItA points_last, OffsetIteratorB linestring_geometry_offsets_first, OffsetIteratorC linestring_part_offsets_first, OffsetIteratorC linestring_part_offsets_last, Vec2dItB linestring_points_first, Vec2dItB linestring_points_last, OutputIt output_first, rmm::cuda_stream_view stream=rmm::cuda_stream_default)
	Compute the nearest points and geometry ID between pairs of multipoint and multilinestring.

Function Documentation

pairwise_point_linestring_nearest_points()

template<class Vec2dItA , class Vec2dItB , class OffsetIteratorA , class OffsetIteratorB , class OffsetIteratorC , class OutputIt >

OutputIt cuspatial::pairwise_point_linestring_nearest_points	(	OffsetIteratorA	points_geometry_offsets_first,
		OffsetIteratorA	points_geometry_offsets_last,
		Vec2dItA	points_first,
		Vec2dItA	points_last,
		OffsetIteratorB	linestring_geometry_offsets_first,
		OffsetIteratorC	linestring_part_offsets_first,
		OffsetIteratorC	linestring_part_offsets_last,
		Vec2dItB	linestring_points_first,
		Vec2dItB	linestring_points_last,
		OutputIt	output_first,
		rmm::cuda_stream_view	stream = rmm::cuda_stream_default )

Compute the nearest points and geometry ID between pairs of multipoint and multilinestring.

The nearest point from a test point to a linestring is a point on the linestring that has the shortest distance to the test point compared to any other points on the linestring.

The nearest point from a test multipoint to a multilinestring is the nearest point that has the shortest distance in all pairs of points and linestrings.

In addition, this API writes these geometry and part ID where the nearest point locates to output iterators:

• The point ID indicates which point in the multipoint is the nearest point.
• The linestring ID is the offset within the multilinestring that contains the nearest point.
• The segment ID is the offset within the linestring of the segment that contains the nearest point. It is the same as the ID of the starting point of the segment.

Template Parameters

Cart2dItA	iterator type for point array of the point element of each pair. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
Cart2dItB	iterator type for point array of the linestring element of each pair. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
OffsetIteratorA	iterator type for point_geometry_offset array. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
OffsetIteratorB	iterator type for linestring_geometry_offset array. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
OffsetIteratorC	iterator type for linestring_part_offset array. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
OutputIt	iterator type for output array. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.

Parameters

point_geometry_offset_first	beginning of the range of multipoint geometries of each pair
point_geometry_offset_last	end of the range of multipoint geometries of each pair
points_first	beginning of the range of point values
points_last	end of the range of the point values
linestring_geometry_offset_first	beginning of the range of offsets to the multilinestring geometry of each pair, the end range is implied by linestring_geometry_offset_first + std::distance(point_geometry_offset_first, point_geometry_offset_last)
linestring_offsets_first	beginning of the range of offsets to the starting point of each linestring
linestring_offsets_last	end of the range of offsets to the starting point of each linestring
linestring_points_first	beginning of the range of linestring points
linestring_points_last	end of the range of linestring points
output_first	A zipped-iterator of 4 outputs. The first element should be compatible with iterator_value_type<OffsetIteratorA>, stores the geometry ID of the nearest point in multipoint. The second element should be compatible with iterator_value_type<OffsetIteratorB>, stores the geometry ID of the nearest linestring. The third element should be compatible with iterator_value_type<OffsetIteratorC>, stores the part ID to the nearest segment. The forth element should be compatible with vec_2d, stores the coordinate of the nearest point on the (multi)linestring.
stream	The CUDA stream to use for device memory operations and kernel launches.

Returns

Output iterator to the element past the last tuple computed.

Precondition

all input iterators for coordinates must have cuspatial::vec_2d type, and must have the same base floating point type.