Split geometry using Boost Library

问题

Is there any way to perform split operation on a geometry using Boost library?

回答1:

I'm not sure what do you have in mind exactly but you could check the algorithms implemented in Boost.Geometry (http://www.boost.org/libs/geometry).

I'm guessing that you could implement it using intersection() or difference() algorithm.

回答2:

You are not specific enough about what is your input and what is your definition of splitting it.

Is there any way to perform split operation on a geometry using Boost library?

Below is my attempt to answer your question with a quick and simple, not necessarily optimal, example of how to use Boost.Geometry building blocks to compose solution (one of many possible) for splitting a geometry, namely, a linestring at given point.

#include <boost/geometry.hpp>
#include <algorithm>
#include <iostream>
#include <vector>
namespace bg = boost::geometry;
using point_2d = bg::model::d2::point_xy<double>;
using linestring_2d = bg::model::linestring<point_2d>;

int main()
{
    point_2d pt(2.5, 0);
    linestring_2d ls({{0, 0}, {1, 0}, {2, 0}, {3, 0}, {4, 0}, {5, 0}});

    auto split_begin = std::find_if(bg::segments_begin(ls), bg::segments_end(ls),
        [&pt](auto const& segment) { return bg::intersects(segment, pt); });

    linestring_2d line1;
    std::for_each(bg::segments_begin(ls), split_begin, [&line1](auto const& s)
    {
        bg::append(line1, s.first);
    });
    bg::append(line1, split_begin->first);
    bg::append(line1, pt);

    linestring_2d line2;
    bg::append(line2, pt);
    bg::append(line2, split_begin->second);
    std::for_each(++split_begin, bg::segments_end(ls), [&line2](auto const& s)
    {
        bg::append(line2, s.second);
    });

    std::cout << "line:        " << bg::dsv(ls) << std::endl;
    std::cout << "split point: " << bg::dsv(pt) << std::endl;
    std::cout << "line1:       " << bg::dsv(line1) << std::endl;
    std::cout << "line2:       " << bg::dsv(line2) << std::endl;
}

Output:

line:        ((0, 0), (1, 0), (2, 0), (3, 0), (4, 0), (5, 0))
split point: (2.5, 0)
line1:       ((0, 0), (1, 0), (2, 0), (2.5, 0))
line2:       ((2.5, 0), (3, 0), (4, 0), (5, 0))

来源：https://stackoverflow.com/questions/15217356/split-geometry-using-boost-library

标签

boost

split

boost-geometry