Boost Geometry 자주 사용하는 함수 정리 1편

boost::geometry::within

• 입력한 두 geometry의 포함 여부를 계산하는 함수
  
  • geometry1이 geometry2에 포함되는지 검사
  • return boolean

column : geometry1 / row : geometry2

template<typename Geometry1, typename Geometry2>
bool within(Geometry1 const & geometry1, Geometry2 const & geometry2)

---

point_t point1;
boost::geometry::model::polygon poly1;
const auto& _isWithIn = boost::geometry::within(point1, poly1);
----> ok
const auto& _isWithIn = boost::geometry::within(poly1, point1);
----> fail

---

boost::geometry::intersects

• 입력한 두 geometry의 충돌 여부를 계산하는 함수
  
  • geometry1이 geometry2와 충돌하는지 검사
  • return boolean

template<typename Geometry1, typename Geometry2>
bool intersects(Geometry1 const & geometry1, Geometry2 const & geometry2)

---

boost::geometry::model::polygon poly1, poly2;
const auto& hasIntersects = boost::geometry::intersects(poly1, poly2);

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boost::geometry::intersection

• 입력된 두 geometry 간 교집합을 계산하는 함수

template<typename Geometry1, typename Geometry2, typename GeometryOut>
bool intersection(Geometry1 const & geometry1, Geometry2 const & geometry2, GeometryOut & geometry_out)

---

void draw_intersection()
{
    boost::geometry::model::polygon green, blue;

    boost::geometry::read_wkt(
        "POLYGON((2 1.3,2.4 1.7,2.8 1.8,3.4 1.2,3.7 1.6,3.4 2,4.1 3,5.3 2.6,5.4 1.2,4.9 0.8,2.9 0.7,2 1.3)"
        "(4.0 2.0, 4.2 1.4, 4.8 1.9, 4.4 2.2, 4.0 2.0))", green);

    boost::geometry::read_wkt(
        "POLYGON((4.0 -0.5 , 3.5 1.0 , 2.0 1.5 , 3.5 2.0 , 4.0 3.5 , 4.5 2.0 , 6.0 1.5 , 4.5 1.0 , 4.0 -0.5))", blue);

    boost::geometry::correct(green);
    boost::geometry::correct(blue);

    boost::geometry::model::multi_polygon output;
    boost::geometry::intersection(green, blue, output);

    int i = 0;
    std::cout << "green && blue:" << std::endl;
    
    std::ofstream svg("draw_intersection.svg");
    boost::geometry::svg_mapper<point_t> mapper(svg, 1024, 1024);

    mapper.add(green);
    mapper.map(green, "fill-opacity:0.5;fill:rgb(0,255,0);stroke:rgb(0,0,0);stroke-width:1", 2);

    mapper.add(blue);
    mapper.map(blue, "fill-opacity:0.5;fill:rgb(0,0,255);stroke:rgb(0,0,0);stroke-width:1", 2);

    mapper.add(output);
    mapper.map(output, "fill-opacity:1.0;fill:rgb(255,0,0);stroke:rgb(0,0,0);stroke-width:1", 2);
}

red : Intersection result

---

boost::geometry::difference

• 입력된 두 geometry 간 차집합을 계산하는 함수

template<typename Geometry1, typename Geometry2, typename Collection>
void difference(Geometry1 const & geometry1, Geometry2 const & geometry2, Collection & output_collection)

---

boost::geometry::model::polygon green, blue;

boost::geometry::read_wkt(
    "POLYGON((2 1.3,2.4 1.7,2.8 1.8,3.4 1.2,3.7 1.6,3.4 2,4.1 3,5.3 2.6,5.4 1.2,4.9 0.8,2.9 0.7,2 1.3)"
    "(4.0 2.0, 4.2 1.4, 4.8 1.9, 4.4 2.2, 4.0 2.0))", green);

boost::geometry::read_wkt(
    "POLYGON((4.0 -0.5 , 3.5 1.0 , 2.0 1.5 , 3.5 2.0 , 4.0 3.5 , 4.5 2.0 , 6.0 1.5 , 4.5 1.0 , 4.0 -0.5))", blue);

boost::geometry::correct(green);
boost::geometry::correct(blue);

boost::geometry::model::multi_polygon output;
boost::geometry::difference(green, blue, output);

int i = 0;
std::cout << "green && blue:" << std::endl;

std::ofstream svg("draw_difference.svg");
boost::geometry::svg_mapper<point_t> mapper(svg, 1024, 1024);


mapper.add(green);
mapper.map(green, "fill-opacity:0.5;fill:rgb(0,255,0);stroke:rgb(0,0,0);stroke-width:1", 2);

mapper.add(blue);
mapper.map(blue, "fill-opacity:0.5;fill:rgb(0,0,255);stroke:rgb(0,0,0);stroke-width:1", 2);

mapper.add(output);
mapper.map(output, "fill-opacity:1.0;fill:rgb(255,0,0);stroke:rgb(0,0,0);stroke-width:1", 2);

red : difference result