我想找到在rtree中索引的所有元素，这些元素与带孔的多边形的外环相交，但是使用Boost C ++库并不完全在任何孔内。
我知道如何让元素与外环相交：
// Constructing the exterior ring polygon
Boost2dRing p;
for (int i = 0; i < numPunts; i++)
{
x = Punts.at(i).x;
y = Punts.at(i).y;
p.push_back(Boost2dPoint(x, y));
}
// Getting the intersecting elements with that polygon
m_RTree.query(bgi::intersects(p), std::back_inserter(res));
...
// Constructing the polygon for the inner ring (hole)
Boost2dRing p;
for (int i = 0; i < numPuntsHole; i++)
{
x = PuntsHole.at(i).x;
y = PuntsHole.at(i).y;
pHole.push_back(Boost2dPoint(x, y));
}
// Now I try to get the elements inside completely this polygon but I get a compilation error
m_RTree.query(bgi::within(pHole), std::back_inserter(res));
错误讯息：
错误C2664：'int 提高:: MPL :: assertion_failed（升压:: MPL ::断言::类型）“： 无法从'boost :: mpl :: failed中转换参数1 ************（__ cdecl boost :: geometry :: strategy :: within :: services :: default_strategy :: NOT_IMPLEMENTED_FOR_THESE_TYPES :: * ***********）（升压:: MPL ::断言_ ::类型）” 'boost :: mpl :: assert :: type'1＆gt;用1> [1> Geometry1 = Boost2dBox，1＆gt; Geometry2 = Boost2dRing，1＆gt;
GeometryContained = Boost2dBox，1＆gt;
GeometryContaining = Boost2dRing 1＆gt; ]注意：没有构造函数 可以采取源类型，或构造函数重载决议 暧昧
有任何提示可以达到这个目标吗？
答案 0 :(得分：1)
对于您选择的几何操作数，未实现内部谓词。
但是，你可以通过很多减少工作来做你想做的事。让我们说你有戒指，例如：
Boost2dRing exterior, interior;
bg::read_wkt("POLYGON((0.1 0.1,0.1 0.5,0.5 0.5,0.5 0.1,0.1 0.1))", exterior);
bg::read_wkt("POLYGON((0.2 0.2,0.2 0.4,0.4 0.4,0.4 0.2,0.2 0.2))", interior);
现在，Boost Geometry具有Polygon的概念，它是一个外环和（多个）内环：
多边形是多边形是由一个外部边界和零个或多个内部边界（OGC Simple Feature Specification）
定义的平面
所以，让我们改用：
bg::reverse(interior);
Boost2dPolygon polygon;
polygon.outer() = exterior;
polygon.inners().push_back(interior);
请注意，内圈的方向是反转的。
或者，实际上，直接使用构造函数：
Boost2dPolygon polygon({exterior, interior});
或者，甚至立即从WKT阅读：
bg::read_wkt("POLYGON((0.1 0.1,0.1 0.5,0.5 0.5,0.5 0.1,0.1 0.1) (0.2 0.2,0.4 0.2,0.4 0.4,0.2 0.4,0.2 0.2))", polygon);
现在你可以一次查询：
std::vector<RTree::value_type> res;
m_RTree.query(bgi::intersects(polygon), std::back_inserter(res));
给出以下sample()树内容：
using RTree = bgi::rtree<std::pair<Boost2dBox, std::string>, bgi::rstar<16> >;
RTree sample() {
RTree tree;
std::pair<std::string, std::string> items[] = {
{ "BOX(0.2 0.2,0.2 0.4,0.4 0.4,0.4 0.2,0.2 0.2)", "ok" },
{ "BOX(0.28 0.28,0.28 0.32,0.32 0.32,0.32 0.28,0.28 0.28)", "within gap" },
{ "BOX(0.28 0.28,0.28 0.32,0.36 0.32,0.36 0.28,0.28 0.28)", "small overlap" },
{ "BOX(2 2,2 4,4 4,4 2,2 2)", "outside exterior" },
};
for (auto& item : items) {
Boost2dBox box;
bg::read_wkt(item.first, box);
checks("box", box);
tree.insert({box, item.second});
}
return tree;
}
我们可以手动测试：
RTree const m_RTree = sample();
std::cout << "Sample tree:\n";
for (auto& value : m_RTree) {
std::cout << " - " << std::quoted(value.second) << ": " << bg::wkt(value.first) << "\n";
Boost2dMultiPolygon mp;
if (bg::intersection(polygon, value.first, mp))
std::cout << " (intersection is " << bg::wkt(mp) << ")\n";
}
打印
Sample tree:
- "ok": POLYGON((0.2 0.2,0.2 0.4,0.4 0.4,0.4 0.2,0.2 0.2))
(intersection is MULTIPOLYGON(((0.2 0.2,0.2 0.4,0.4 0.4,0.4 0.2,0.2 0.2),(0.25 0.25,0.35 0.25,0.35 0.35,0.25 0.35,0.25 0.25))))
- "within gap": POLYGON((0.28 0.28,0.28 0.32,0.32 0.32,0.32 0.28,0.28 0.28))
(intersection is MULTIPOLYGON())
- "small overlap": POLYGON((0.28 0.28,0.28 0.32,0.36 0.32,0.36 0.28,0.28 0.28))
(intersection is MULTIPOLYGON(((0.35 0.32,0.36 0.32,0.36 0.28,0.35 0.28,0.35 0.32))))
- "outside exterior": POLYGON((2 2,2 4,4 4,4 2,2 2))
(intersection is MULTIPOLYGON())
并验证与树查询比较的结果：
m_RTree.query(bgi::intersects(polygon), std::back_inserter(matches));
std::cout << "Intersecting with: ";
for (auto& match : matches) std::cout << " " << std::quoted(match.second) << " ";
打印哪些：
Intersecting with: "ok" "small overlap"
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#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/multi_polygon.hpp>
#include <boost/geometry/geometries/linestring.hpp>
#include <boost/geometry/geometries/multi_polygon.hpp>
#include <boost/geometry/core/cs.hpp>
#include <boost/geometry/arithmetic/arithmetic.hpp>
#include <boost/geometry/algorithms/within.hpp>
#include <boost/geometry/algorithms/intersects.hpp>
#include <boost/geometry/algorithms/envelope.hpp>
#include <boost/geometry/algorithms/intersection.hpp>
#include <boost/geometry/index/rtree.hpp>
#include <boost/geometry/index/predicates.hpp>
#include <boost/geometry/index/adaptors/query.hpp>
#include <boost/geometry/io/io.hpp>
#include <iostream>
#include <fstream>
namespace bg = boost::geometry;
namespace bgi = boost::geometry::index;
using Boost2dPoint = bg::model::d2::point_xy<double>;
using Boost2dRing = bg::model::ring<Boost2dPoint>;
using Boost2dPolygon = bg::model::polygon<Boost2dPoint>;
using Boost2dMultiPolygon = bg::model::multi_polygon<Boost2dPolygon>;
using Boost2dBox = bg::model::box<Boost2dPoint>;
template <typename G> void checks(std::string name, G& geom) {
std::cout << name << ": " << bg::wkt(geom) << "\n";
std::string reason;
if (!bg::is_valid(geom, reason)) {
std::cout << name << ": " << reason << "\n";
bg::correct(geom);
std::cout << bg::wkt(geom) << "\n";
if (!bg::is_valid(geom, reason)) {
std::cout << name << " corrected: " << reason << "\n";
}
}
}
using RTree = bgi::rtree<std::pair<Boost2dBox, std::string>, bgi::rstar<16> >;
RTree sample() {
RTree tree;
std::pair<std::string, std::string> items[] = {
{ "BOX(0.2 0.2,0.2 0.4,0.4 0.4,0.4 0.2,0.2 0.2)", "ok" },
{ "BOX(0.28 0.28,0.28 0.32,0.32 0.32,0.32 0.28,0.28 0.28)", "within gap" },
{ "BOX(0.28 0.28,0.28 0.32,0.36 0.32,0.36 0.28,0.28 0.28)", "small overlap" },
{ "BOX(2 2,2 4,4 4,4 2,2 2)", "outside exterior" },
};
for (auto& item : items) {
Boost2dBox box;
bg::read_wkt(item.first, box);
checks("box", box);
tree.insert({box, item.second});
}
return tree;
}
int main() {
Boost2dPolygon polygon;
bg::read_wkt("POLYGON((0.1 0.1,0.1 0.5,0.5 0.5,0.5 0.1,0.1 0.1) (0.25 0.25,0.35 0.25,0.35 0.35,0.25 0.35,0.25 0.25))", polygon);
checks("polygon", polygon);
RTree const m_RTree = sample();
std::cout << "Sample tree:\n";
for (auto& value : m_RTree) {
std::cout << " - " << std::quoted(value.second) << ": " << bg::wkt(value.first) << "\n";
Boost2dMultiPolygon mp;
if (bg::intersection(polygon, value.first, mp))
std::cout << " (intersection is " << bg::wkt(mp) << ")\n";
}
std::cout << "\n";
std::vector<RTree::value_type> matches;
m_RTree.query(bgi::intersects(polygon), std::back_inserter(matches));
std::cout << "Intersecting with: ";
for (auto& match : matches) std::cout << " " << std::quoted(match.second) << " ";
std::cout << "\n";
}