Bing地图多边形搜索不准确

Question

我在这里找到的bing maps示例Polygon Search遇到了一些问题:

多边形搜索大约是此链接的一半.

  public bool polygonSearch(LocationCollection points, double lat, double lon)
{
    MapPolygon poly = new MapPolygon();

    int i = 0;
    int j = points.Count - 1;
    bool inPoly = false;

    for (i = 0; i < points.Count; i++)
    {
        if (points[i].Longitude < lon && points[j].Longitude >= lon || points[j].Longitude < lon && points[i].Longitude >= lon)
        {
            if (points[i].Latitude + (lon - points[i].Longitude) / (points[j].Longitude - points[i].Longitude) * (points[j].Latitude - points[i].Latitude) < lat)
            {
                inPoly = !inPoly;

            }
        }
        j = i;
    }

    return inPoly;



}

我ViewportPointToLocation用来获取鼠标坐标并在鼠标点击时添加一个引脚.

            Point mousePosition = e.GetPosition(myMap);
            Microsoft.Maps.MapControl.WPF.Location pinLocation = myMap.ViewportPointToLocation(mousePosition);
            // Convert the mouse coordinates to a location on the map 


            // The pushpin to add to the map.
            Pushpin pin = new Pushpin();
            pin.Location = pinLocation;
            pin.Content = "Cust";
            pin.Heading = 0;

            // Adds the pushpin to the map
            myMap.Children.Add(pin);

这是我使用多边形搜索来查看是否在多边形内单击.

polygonSearch(polygon.Locations, pin.Location.Latitude, pin.Location.Longitude))

如下图所示,我将标签设置为"交付区域内"或"客户区域外",具体取决于天气polygonSearch返回true或false.

处理多边形边缘时似乎不起作用.有人可以更多地体验这个让我知道我哪里错了吗？

完整的代码示例如下:

您将需要参考以Microsoft.Maps.MapControl.WPF.dll使其工作.

我做了一个演示,其中包含bing地图控制图,一个告诉我们多边形搜索输出的标签,以及一个允许你在多边形内搜索的复选框.

要制作多边形,只需右键单击要绘制的地图,然后按"Escape"结束绘制多边形.然后,您可以单击"左键单击搜索地址"复选框,然后在多边形内搜索.

正如您将看到的,当我们看到我们在刚刚绘制的多边形内单击时,MSDN中的多边形搜索会返回区域外!

MainWindow.xaml

<Window x:Class="PolygonSearch.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:m="clr-namespace:Microsoft.Maps.MapControl.WPF;assembly=Microsoft.Maps.MapControl.WPF"
        Title="MainWindow" Height="350" Width="525" KeyDown="Window_KeyDown">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="100*"/>
        </Grid.RowDefinitions>
        <StackPanel>
        <Label Content="Label" Height="28" HorizontalAlignment="Left" Margin="10,10,0,0" Name="lbl_arearsult" Grid.Row="0" VerticalAlignment="Top" />
        <CheckBox Content="Search Address by left click" Height="16" HorizontalAlignment="Left" Margin="10,10,0,0" Name="chk_search" VerticalAlignment="Top" />
        </StackPanel>
        <m:Map x:Name="myMap" Grid.Row="1" CredentialsProvider="your_bing_map_key" Mode="AerialWithLabels" MouseLeftButtonDown="myMap_MouseDown" MouseRightButtonDown="myMap_MouseRightButtonDown" KeyDown="myMap_KeyDown" />

    </Grid>
</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

using Microsoft.Maps.MapControl.WPF;

namespace PolygonSearch
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        LocationCollection drawPolyPoints = new LocationCollection();

        public MainWindow()
        {
            InitializeComponent();
        }



        public bool polygonSearch(LocationCollection points, double lat, double lon)
        {
            MapPolygon poly = new MapPolygon();

            int i = 0;
            int j = points.Count - 1;
            bool inPoly = false;

            for (i = 0; i < points.Count; i++)
            {
                if (points[i].Longitude < lon && points[j].Longitude >= lon || points[j].Longitude < lon && points[i].Longitude >= lon)
                {
                    if (points[i].Latitude + (lon - points[i].Longitude) / (points[j].Longitude - points[i].Longitude) * (points[j].Latitude - points[i].Latitude) < lat)
                    {
                        inPoly = !inPoly;

                    }
                }
                j = i;
            }

            return inPoly;



        }

        private void myMap_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == System.Windows.Input.Key.Escape)
            {
                MapPolygon polygon = new MapPolygon();
                polygon.Fill = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Colors.Blue);
                polygon.Stroke = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Colors.Green);
                polygon.StrokeThickness = 5;
                polygon.Opacity = 0.7;
                polygon.Locations = drawPolyPoints;
                polygon.Tag = "1388_q3_polygon_5";
                myMap.Children.Add(polygon);
                //drawPolyPoints.Clear();

                for (int p = 0; p < myMap.Children.Count; p++)
                {
                    object entity = myMap.Children[p];
                    if (entity is Microsoft.Maps.MapControl.WPF.Pushpin)
                    {
                        if (((Microsoft.Maps.MapControl.WPF.Pushpin)entity).Content.ToString() == "Vertice")
                            myMap.Children.Remove(((Microsoft.Maps.MapControl.WPF.Pushpin)entity));
                    }


                }
            }
        }

        private void myMap_MouseDown(object sender, MouseButtonEventArgs e)
        {
            if (chk_search.IsChecked == true)
            {
                Point mousePosition = e.GetPosition(myMap);
                Microsoft.Maps.MapControl.WPF.Location pinLocation = myMap.ViewportPointToLocation(mousePosition);
                // Convert the mouse coordinates to a location on the map 


                // The pushpin to add to the map.
                Pushpin pin = new Pushpin();
                pin.Location = pinLocation;
                pin.Content = "Cust";
                pin.Heading = 0;

                // Adds the pushpin to the map
                myMap.Children.Add(pin);

                bool inArea = false;
                for (int p = 0; p < myMap.Children.Count; p++)
                {
                    object entity = myMap.Children[p];


                    if (entity is Microsoft.Maps.MapControl.WPF.MapPolygon)
                    {
                        if (polygonSearch(((Microsoft.Maps.MapControl.WPF.MapPolygon)entity).Locations, pin.Location.Latitude, pin.Location.Longitude))
                        {
                            string[] quadAttributes = ((Microsoft.Maps.MapControl.WPF.MapPolygon)entity).Tag.ToString().Split('_');

                            lbl_arearsult.Content = "Within delivery area ";

                            inArea = true;
                            break;
                        }
                        else
                        {

                            inArea = false;

                        }

                    }
                }
                if (inArea != true)
                    lbl_arearsult.Content = "Customer out of area. ";
            }

        }

        private void myMap_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
        {
            Point mousePosition = e.GetPosition(myMap);
            Microsoft.Maps.MapControl.WPF.Location pinLocation = myMap.ViewportPointToLocation(mousePosition);
            // Convert the mouse coordinates to a location on the map 

            // The pushpin to add to the map.
            Pushpin pin = new Pushpin();
            pin.Location = pinLocation;
            pin.Content = "Vertice";

            // Adds the pushpin to the map
            myMap.Children.Add(pin);
            drawPolyPoints.Add(pin.Location);
        }

        private void Window_KeyDown(object sender, KeyEventArgs e)
        {
            myMap_KeyDown(sender, e);
        }
    }
}

注意:此设计仅用于创建1个要搜索的多边形,但您仍然可以看到我的多边形搜索在视觉上失败的位置.

编辑:

• 非常感谢KeyboardP,我们发现如果您完全放大,然后绘制多边形,然后搜索,则问题不存在.但如果我们绘制它,然后缩放,我们将看到同样的问题出现.

• 我还调试并确认了LocationCollection多边形在不同的缩放级别上是相同的

• 项目清单

Answer 1

我大约6年前写过这篇文章.这是多边形算法中的一个简单点,它基于标准2D几何,并且不是地理空间精确的算法.它适用于覆盖城市或更小区域的小多边形.大多边形似乎不太准确.注意地图上两点之间的一条线,即使它看起来很直,实际上该线是弯曲的.这方面的一个很好的例子可以在这里找到:http://alastaira.wordpress.com/2011/06/27/geodesics-on-bing-maps-v7/

至于您的问题,如果您想单击多边形,只需使用鼠标事件.如果要检查点是否在多边形中,那么您可以使用WPF中功能强大的SQL Spatial库,它将为您提供多边形计算中的地理空间精确点.您不需要连接到数据库.您只需要通过SQL Express免费获得的Microsoft.SqlServer.Types.dll.您可以在.NET中使用它并使用Bing Maps WPF控件.这是一个很好的起点:http://ecn.channel9.msdn.com/o9/learn/SQL2008R2TrainingKit/Labs/UsingSpatialDataInManagedCode/Lab.docx

一旦你有了这个工作,你就可以简单地从多边形中创建一个SQLGeography对象,并检查你的点是否与多边形相交.

Answer 2

我通过使用函数将所有多边形纬度/经度转换为Point屏幕上的对象LocationToViewPortpoint以及我正在测试相交的点来修复此问题，并在多边形搜索中使用 X 和 Y 值而不是纬度/经度。