4
私は2つの有効なポリゴンを持っています。彼らの組合を取るとき、私は無効な多角形を得ています（自己交点があります）。これはバグですか？私は、ユニオン演算が常に有効なポリゴンを生成することを期待しています。私は視覚化と一緒に下の例を提供しました。なぜこれがバグではないのか説明することができますか、それを修正する方法があるかどうか説明してください。boost :: geometry :: union_は自己交差を生成します
#include <fstream>
#include <iostream>
#include <boost/geometry.hpp> // read_wkt
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/polygon.hpp>
#include <boost/geometry/geometries/multi_polygon.hpp>
#include <boost/geometry/algorithms/union.hpp>
using PointType = boost::geometry::model::d2::point_xy<double>;
using PolygonType = boost::geometry::model::polygon<PointType>;
using MultiPolygonType = boost::geometry::model::multi_polygon<PolygonType>;
template <typename TPolygon>
void WritePolygonsToSVG(const std::vector<TPolygon>& polygons, const std::string& filename)
{
std::ofstream svg(filename);
boost::geometry::svg_mapper<PointType> mapper(svg, 400, 400);
for(unsigned int i = 0; i < polygons.size(); ++i) {
mapper.add(polygons[i]);
mapper.map(polygons[i], "fill:rgb(255,128,0);stroke:rgb(0,0,100);stroke-width:1");
}
}
int main(int, char**)
{
/// Create two polygons
PolygonType singlePolygon1;
PolygonType singlePolygon2;
boost::geometry::read_wkt("POLYGON((-52.8018 -26.744,-57.5465 -27.9916,-62.2844 -29.2642,-63.19 -26.066,-57.564 -24.5243,-53.7273 -23.3394,-52.8018 -26.744))", singlePolygon1);
boost::geometry::read_wkt("POLYGON((-56.9695 -33.6407,-58.009 -33.0132,-58.5119 -32.8011,-59.0182 -32.6562,-59.5392 -32.5779,-60.0858 -32.5658,"
"-61.3005 -32.7384,-62.2844 -29.2642,-59.997 -28.7264,-58.0701 -28.125,-56.7078 -27.7124,-55.3109 -27.4556,-55.0955 -27.4599,"
"-54.8762 -27.503,-54.6545 -27.5806,-54.4318 -27.6887,-53.9893 -27.98,-53.5601 -28.344,-52.7879 -29.1592,-52.207 -29.8722,-56.9695 -33.6407))", singlePolygon2);
boost::geometry::correct(singlePolygon1);
boost::geometry::correct(singlePolygon2);
/// Run union and check validity (should fail check)
MultiPolygonType unionResult;
boost::geometry::union_(singlePolygon1, singlePolygon2, unionResult);
boost::geometry::validity_failure_type failure_type;
if(!boost::geometry::is_valid(unionResult, failure_type)) {
std::cout << "Result of union operation is not valid! " << failure_type << std::endl; // failure_type is 21 == failure_self_intersections
}
// Put these into the same type so that they can be passed to WritePolygonsToSVG
MultiPolygonType polygon1;
polygon1.push_back(singlePolygon1);
MultiPolygonType polygon2;
polygon2.push_back(singlePolygon2);
std::vector<MultiPolygonType> polygons = {polygon1, polygon2, unionResult};
WritePolygonsToSVG(polygons, "allPolygons.svg");
return EXIT_SUCCESS;
}
Polygon1： 
Polygon2： 
両方の入力ポリゴン： 
ユニオンポリゴン（自己交差）： 
terminate called after throwing an instance of 'boost::geometry::overlay_invalid_input_exception'
what(): Boost.Geometry Overlay invalid input exception
この拡張された例では、例外を示しています：
私はに実行している実際の問題は、私はその後、労働組合に他のポリゴンと（無効）出力ポリゴンをしようとすると、それが例外をスローということです#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/polygon.hpp>
#include <boost/geometry/geometries/multi_polygon.hpp>
#include <boost/geometry/algorithms/assign.hpp>
#include <boost/geometry/algorithms/intersection.hpp>
#include <boost/geometry/algorithms/union.hpp>
int main(int argc, char** argv) {
using PointType = boost::geometry::model::d2::point_xy<double>;
using PolygonType = boost::geometry::model::polygon<PointType>;
using MultiPolygonType = boost::geometry::model::multi_polygon<PolygonType>;
/// Read in two polygons
PolygonType polygon1;
PolygonType polygon2;
boost::geometry::read_wkt("POLYGON((-52.8018 -26.744,-57.5465 -27.9916,-62.2844 -29.2642,-63.19 -26.066,-57.564 -24.5243,-53.7273 -23.3394,-52.8018 -26.744))", polygon1);
boost::geometry::read_wkt("POLYGON((-56.9695 -33.6407,-58.009 -33.0132,-58.5119 -32.8011,-59.0182 -32.6562,-59.5392 -32.5779,-60.0858 -32.5658,"
"-61.3005 -32.7384,-62.2844 -29.2642,-59.997 -28.7264,-58.0701 -28.125,-56.7078 -27.7124,-55.3109 -27.4556,-55.0955 -27.4599,"
"-54.8762 -27.503,-54.6545 -27.5806,-54.4318 -27.6887,-53.9893 -27.98,-53.5601 -28.344,-52.7879 -29.1592,-52.207 -29.8722,-56.9695 -33.6407))", polygon2);
/// Run union and check validity (should fail check)
MultiPolygonType unionResult1;
boost::geometry::union_(polygon1, polygon2, unionResult1);
boost::geometry::validity_failure_type failure_type;
if(!boost::geometry::is_valid(unionResult1, failure_type)) {
std::cout << "Result of union operation is not valid!" << std::endl;
}
/// Perform second union with third polygon (should throw)
MultiPolygonType polygon3;
boost::geometry::read_wkt("MULTIPOLYGON(((-36.5181 -22.1798,-39.072 -22.991,-41.6641 -23.6833,-52.8018 -26.744,-53.7273 -23.3394,-45.7888 -21.0022,"
"-41.8671 -19.6963,-37.9783 -18.2852,-36.5181 -22.1798)),((-52.207 -29.8722,-51.6368 -30.7643,-51.1556 -31.8424,-50.7568 -33.0527,"
"-50.4336 -34.3414,-49.9875 -36.9394,-49.8512 -38.1412,-49.7639 -39.2066,-54.0482 -39.4903,-54.1623 -38.8728,-54.4115 -38.1178,"
"-55.1907 -36.4023,-56.1365 -34.758,-56.594 -34.092,-57.0005 -33.5988,-57.0016 -33.5993,-57.0036 -33.6033,-57.0033 -33.6044,"
"-57.0029 -33.6055,-57.0014 -33.6079,-56.9995 -33.6106,-56.9941 -33.6165,-56.9695 -33.6407,-52.207 -29.8722)),((-61.3005 -32.7384,"
"-65.9902 -34.1028,-70.659 -35.5553,-75.2871 -37.1219,-79.8551 -38.829,-84.6551 -40.8483,-87.0116 -41.984,-89.2911 -43.2272,-92.5791 -37.6053,"
"-89.0742 -35.6754,-85.5037 -33.9031,-78.2194 -30.6022,-74.8627 -29.2273,-71.9907 -28.2985,-69.0648 -27.5347,-63.19 -26.066,-61.3005 -32.7384)),"
"((75.3002 -38.7765,72.918 -39.2671,70.5558 -39.533,68.2188 -39.5707,65.912 -39.3766,63.6406 -38.9473,61.4095 -38.2792,59.2239 -37.3688,"
"57.089 -36.2125,55.5367 -35.1756,54.0721 -34.0078,52.7036 -32.7209,51.4398 -31.3265,50.2893 -29.8362,49.2607 -28.2616,48.3624 -26.6144,"
"47.6032 -24.9062,47.158 -23.7161,46.803 -22.6211,46.3142 -20.5856,46.0379 -18.5376,45.9485 -17.427,45.8751 -16.215,45.5849 -10.2471,"
"45.4467 -7.25562,45.2962 -4.26324,45.0667 0.0336182,44.8334 4.32845,44.3738 10.6768,42.9884 29.2827,42.3055 38.5987,41.6559 47.9296,"
"45.1275 48.1622,45.7738 38.8379,46.4466 29.5288,47.7834 10.934,48.2323 4.58677,48.587 0.296648,48.9992 -4.00063,49.299 -6.95733,"
"49.6132 -9.93119,50.1835 -15.8585,50.3639 -17.8241,50.6215 -19.6471,51.0408 -21.4515,51.7068 -23.3609,52.3326 -24.729,53.0701 -26.047,"
"53.9117 -27.3065,54.8496 -28.4987,55.8759 -29.6152,56.9829 -30.6474,58.1629 -31.5867,59.408 -32.4246,60.9346 -33.2618,62.5325 -33.9455,"
"64.1878 -34.476,65.8864 -34.8539,67.3309 -35.051,68.7878 -35.1355,70.2399 -35.1053,72.7143 -34.7658,74.0086 -34.5489,75.3002 -38.7765)))", polygon3);
MultiPolygonType unionResult2;
boost::geometry::union_(unionResult1, polygon3, unionResult2); // throws
std::cout << "Result: " << boost::geometry::wkt(unionResult2) << std::endl;
return EXIT_SUCCESS;
}
あなたは「自己交差」とはどういう意味ですか？私にとって、「ユニオンポリゴン」のイメージは、有効なポリゴンのように見えます。まさに、何が生産されると思いますか？ – Yakk
@Yakkこれは 'is_valid（）'によって報告された失敗のタイプです。私が抱えている問題は、この 'unionResult'ポリゴンと別のポリゴンを結合すると、例外をスローします。 'boost :: geometry :: overlay_invalid_input_exception'のインスタンスをスローした後に終了します。 what（）：ブースト。ジオメトリオーバーレイ無効な入力例外 "。例外に表示するために質問にさらにコードを追加しました。 –
このようなクエリは、私が1.58.0を使用していた正確なブーストバージョン – sehe