Question

我试图遍历boost多边形中的点以对它们执行操作。要显示我的问题的简化版本：

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>

typedef boost::geometry::model::d2::point_xy<double> point_type;
typedef boost::geometry::model::polygon<point_type> polygon;

int main()
{
    polygon polygonTest;
    boost::geometry::read_wkt("POLYGON((-2 2, 2 2, 2 -2, -2 -2, -2 2))", polygonTest);

    for (point_type point : boost::geometry::exterior_ring(polygonTest))
    {
        double xCoord = point.x;
    }


    return 0;
}

我收到以下错误：

'boost::geometry::model::d2::point_xy<double,boost::geometry::cs::cartesian>::x': function call missing argument list; use '&boost::geometry::model::d2::point_xy<double,boost::geometry::cs::cartesian>::x' to create a pointer to member

我忽略了解决这个问题的方法？

Answer 1

您正在使用成员函数 x。但是你忘了叫它：

    double xCoord = point.x();

请参阅下面的工作样本

问。我在忽视什么

您忽略了错误消息中的信息。

GCC：error: cannot resolve overloaded function ‘x’ based on conversion to type ‘double’

它告诉你，你要将一个函数x分配给一个双...
Clang：error: reference to non-static member function must be called; did you mean to call it with no arguments?

它甚至会列出您可能需要的重载

<强> Live On Coliru

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>

typedef boost::geometry::model::d2::point_xy<double> point_type;
typedef boost::geometry::model::polygon<point_type> polygon;

int main() {
    polygon polygonTest;
    boost::geometry::read_wkt("POLYGON((-2 2, 2 2, 2 -2, -2 -2, -2 2))", polygonTest);

    for (point_type point : boost::geometry::exterior_ring(polygonTest)) {
        double xCoord = point.x();
    }
}

访问boost :: geometry多边形时访问点数据时出错

1 个答案: