如何在 C# 中获取 KML 多边形和多几何值？

Question

我可以使用此代码读取和获取 KML 数据地标值

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            XDocument doc = XDocument.Load(FILENAME);
            List<XElement> placemarks = doc.Descendants().Where(x => x.Name.LocalName == "Placemark").ToList();
            List<string> states = placemarks.Descendants().Where(x => x.Name.LocalName == "name").Select(x => x.Value).ToList();
        }
    }

}

但如果KML数据有以下详细信息，我不知道如何获取：

1. 示例：阿拉巴马州 KML 格式类似

   <Polygon> <outerBoundaryIs> <LinearRing> <coordinates>-85.070067,31.980703,0.0 -85.11515,31.907425,0.0 -85.135567,31.854884,0.0 -85.0567,32.017377,0.0 -85.070067,31.980703,0.0</coordinates> </LinearRing> </outerBoundaryIs> </Polygon>

2. 示例：德克萨斯州 KML 格式，如

   <MultiGeometry> <Polygon> <outerBoundaryIs> <LinearRing> <coordinates>-161.333785,58.703653</coordinates> </LinearRing> </outerBoundaryIs> </Polygon> <Polygon> <outerBoundaryIs> <LinearRing> <coordinates>-131.594177,55.106316,55.23548,0.0</coordinates> </LinearRing> </outerBoundaryIs> </Polygon> </MultiGeometry>

我尝试了这个LINQ 程序来获取多边形值：

List<string> states = placemarks.Descendants().Where(x => x.Name.LocalName == "Polygon").Select(x => x.Value).ToList();

输出：

-85.070067,31.980703,0.0 -85.11515,31.907425,0.0 -85.135567,31.854884,0.0 -85.0567,32.017377,0.0 -85.070067,31.980703,0.0

在我尝试替换如下所示格式的坐标并将它们复制/粘贴到融合表位置预览中后，地图完全按预期工作。

<Polygon> <outerBoundaryIs> <LinearRing> <coordinates>-85.070067,31.980703,0.0 -85.11515,31.907425,0.0 -85.135567,31.854884,0.0 -85.0567,32.017377,0.0 -85.070067,31.980703,0.0</coordinates> </LinearRing> </outerBoundaryIs> </Polygon>

但是当我尝试使用相同的方式获取 Multigeometry 值时：

List<string> states = placemarks.Descendants().Where(x => x.Name.LocalName == "MultiGeometry").Select(x => x.Value).ToList();

我得到了这个输出：

-161.333785,58.703653 -131.594177,55.106316,55.23548,0.0

但我不知道如何获取详细信息。

Answer 1

“在我尝试替换如下所示格式的坐标并将它们复制/粘贴到融合表位置预览中后，地图完全按预期工作。”

<Polygon> <outerBoundaryIs> <LinearRing> <coordinates>-85.070067,31.980703,0.0 -85.11515,31.907425,0.0 -85.135567,31.854884,0.0 -85.0567,32.017377,0.0 -85.070067,31.980703,0.0</coordinates> </LinearRing> </outerBoundaryIs> </Polygon>

如果您想要 XElement 的 XML 标记，只需调用 ToString() 而不是获取它的 Value 属性：

List<string> states = placemarks.Descendants()
                                .Where(x => x.Name.LocalName == "MultiGeometry")
                                .Select(x => x.ToString())
                                .ToList();

..或者如果您真的想从MultiGeometry 获取单个坐标值：

List<string> states = placemarks.Descendants()
                                .Where(x => x.Name.LocalName == "MultiGeometry")
                                .Descendants()
                                .Where(x => x.Name.LocalName == "Polygon")
                                .Select(x => x.Value)
                                .ToList();