在Xamarin Google Maps for Android使用C＃的基础上，您可以根据本教程创建多边形：
public void OnMapReady(GoogleMap googleMap)
{
mMap = googleMap;
PolylineOptions geometry = new PolylineOptions()
.Add(new LatLng(37.35, -37.0123))
.Add(new LatLng(37.35, -37.0123))
.Add(new LatLng(37.35, -37.0123));
Polyline polyline = mMap.AddPolyline(geometry);
}
但是，我已经从Google地图的Fusion Table图层中下载了CSV文件，因为我认为这可能是处理面/折线数据的最简单选择。输出如下所示：
description,name,label,geometry
,Highland,61,"<Polygon><outerBoundaryIs><LinearRing><coordinates>-5.657018,57.3352 -5.656396,57.334463 -5.655076,57.334556 -5.653439,57.334477 -5.652366,57.334724 -5.650064,57.334477 -5.648096,57.335082 -5.646846,57.335388 -5.644733,57.335539 -5.643309,57.335428 -5.641981,57.335448 -5.640451,57.33578 -5.633217,57.339118 -5.627278,57.338921 -5.617161,57.337649 -5.607948,57.341015 -5.595812,57.343583 -5.586043,57.345373 -5.583581,57.350648 -5.576851,57.353609 -5.570088,57.354017 -5.560732,57.354102 -5.555254,57.354033 -5.549713,57.353146 -5.547766,57.352275 -5.538932,57.352255 -5.525891,57.356217 -5.514888,57.361865 -5.504272,57.366027 -5.494515,57.374515 -5.469829,57.383765 -5.458661,57.389781 -5.453695,57.395033 -5.454057,57.402943 -5.449189,57.40731 -5.440583,57.411447 -5.436133,57.414616 -5.438312,57.415474 -5.438628,57.417955 -5.440956,57.417909 -5.444013,57.414976 -5.450778,57.421362 -5.455035,57.422333 -5.462081,57.420719 -5.468775,57.416975 -5.475205,57.41135 -5.475976,57.409117 -5.47705,57.407092 -5.478101,57.406056 -5.478901,57.40536 -5.479489,57.404534 -5.480051,57.403782 -5.481036,57.403107 -5.484538,57.402102 -5.485647,57.401856 -5.487358,57.401287 -5.488709,57.400962 -5.490175,57.400616 -5.491116,57.400176 -5.493832,57.399318 -5.495279,57.399134 -5.496726,57.39771 -5.498724,57.396836 -5.49974,57.396314 -5.501317,57.39627 -5.502869,57.395426</coordinates></LinearRing></innerBoundaryIs></Polygon>"
,Strathclyde,63,"<Polygon><outerBoundaryIs><LinearRing><coordinates>-5.603129,56.313564 -5.603163,56.312536 -5.603643,56.311794 -5.601467,56.311875 -5.601038,56.312481 -5.600697,56.313489 -5.60071,56.31535 -5.60159,56.316107 -5.600729,56.316598 -5.598625,56.316058 -5.596203,56.317477 -5.597024,56.318119 -5.596095,56.318739 -5.595432,56.320116 -5.589343,56.322469 -5.584888,56.325178 -5.582907,56.327169 -5.581414,56.327472 -5.581435,56.326663 -5.582355,56.325602 -5.581515,56.323891 -5.576993,56.331062 -5.57886,56.331475 -5.57676,56.334449 -5.572748,56.335689 -5.569012,56.338143 -5.564802,56.342113 -5.555237,56.346668 -5.551214,56.347448 -5.547651,56.346391 -5.54444,56.344945 -5.541247,56.345945 -5.539099,56.349674 -5.533874,56.34763 -5.525195,56.342888 -5.523518,56.345066 -5.52345,56.346605 -5.526417,56.354361 -5.535455,56.353681 -5.537463,56.35508 -5.536035,56.356271 -5.538923,56.357205 -5.53891,56.359336 -5.539952,56.361491 -5.538102,56.36372 -5.535934,56.36567 -5.53392,56.367705 -5.531369,56.369729 -5.529853,56.371022 -5.532371,56.371274 -5.534177,56.371708 -5.532846,56.373256 -5.529845,56.37496 -5.527675,56.375327 -5.528531,56.375995 -5.526732,56.376343 -5.525442,56.377809 -5.524739,56.379843 -5.526069,56.380561</coordinates></LinearRing></innerBoundaryIs></Polygon>"
我将KML文件上传到Google Maps Fusion Table Layer，然后创建了地图。然后我去File>Download>CSV了，上面的例子给了我。
我已将此csv文件添加到我的xamarin android google map应用程序的assets文件夹中，我的问题是因为LatLng将两个双精度数作为其输入，有没有办法我可以将上述csv文件中的数据输入到此方法中，如果可以怎么样？
不确定如何read the above csv提取<coordinates>，然后将这些坐标添加为LatLng上述示例代码中的新坐标吗？
但是，如果您注意到坐标被划分为lat和lng，那么下一个latlng将以空格 分隔-5.657018,57.3352 -5.656396,57.334463。
Sudo代码（这可能会或可能不需要xamarin或android经验，可能只需要C＃/ Linq）：
Read CSV var sr = new StreamReader(Read csv from Asset folder);
Remove description,name,label,geometry
Foreach line in CSV
Extract Item that contains double qoutes
Foreach Item Remove Qoutes and <Polygon><outerBoundaryIs><LinearRing><coordinates> from start and end
Foreach item seperated by a space Extract coordinates
(This will now leave a long list of 37.35,-37.0123 coordinates for each line)
Place in something like this maybe?:
public class Row
{
public double Lat { get; set; }
public double Lng { get; set; }
public Row(string str)
{
string[] separator = { "," };
var arr = str.Split(separator, StringSplitOptions.None);
Lat = Convert.ToDouble(arr[0]);
Lng = Convert.ToDouble(arr[1]);
}
}
private void OnMapReady()
var rows = new List<Row>();
Foreach name/new line
PolylineOptions geometry = new PolylineOptions()
ForEach (item in rows) //not sure how polyline options will take a foreach
.Add(New LatLng(item.Lat, item.Lng))
Polyline polyline = mMap.AddPolyline(geometry);
由于无法在Xamarin Android中将Fusion Table Layers与Google Maps API v2结合使用，因此对于需要将地图分为区域的用户而言，这可能提供一种快速简便的解决方法。
如果我理解正确，那么问题是如何解析上述CSV文件。
每行（第一行除外，带有标题）可以用以下类表示：
class MapEntry
{
public string Description { get; set; }
public string Name { get; set; }
public string Label { get; set; }
public IEnumerable<LatLng> InnerCoordinates { get; set; }
public IEnumerable<LatLng> OuterCoordinates { get; set; }
}
注意Inner和Outer坐标。它们在XML内部由outerBoundaryIs（必需）和innerBoundaryIs（可选）元素表示。
注意：Highland帖子中的行不正确-您似乎修剪了行的一部分，导致XML（<outerBoundaryIs>...</innerBoundaryIs>）错误。
这是执行解析的代码：
static IEnumerable<MapEntry> ParseMap(string csvFile)
{
return from line in File.ReadLines(csvFile).Skip(1)
let tokens = line.Split(new[] { ',' }, 4)
let xmlToken = tokens[3]
let xmlText = xmlToken.Substring(1, xmlToken.Length - 2)
let xmlRoot = XElement.Parse(xmlText)
select new MapEntry
{
Description = tokens[0],
Name = tokens[1],
Label = tokens[2],
InnerCoordinates = GetCoordinates(xmlRoot.Element("innerBoundaryIs")),
OuterCoordinates = GetCoordinates(xmlRoot.Element("outerBoundaryIs")),
};
}
static IEnumerable<LatLng> GetCoordinates(XElement node)
{
if (node == null) return Enumerable.Empty<LatLng>();
var element = node.Element("LinearRing").Element("coordinates");
return from token in element.Value.Split(' ')
let values = token.Split(',')
select new LatLng(XmlConvert.ToDouble(values[0]), XmlConvert.ToDouble(values[1]));
}
我认为代码是不言自明的。唯一要提及的细节是：
let tokens = line.Split(new[] { ',' }, 4)
在这里，我们使用string.Split 重载，该重载允许我们指定要返回的最大子字符串数，从而避免了处理XML令牌内的逗号的陷阱。
和：
let xmlText = xmlToken.Substring(1, xmlToken.Length - 2)
从XML令牌中去除引号。
最后，您的案例的用法示例：
foreach (var entry in ParseMap(csv_file_full_path))
{
PolylineOptions geometry = new PolylineOptions()
foreach (var item in entry.OuterCoordinates)
geometry.Add(item)
Polyline polyline = mMap.AddPolyline(geometry);
}
更新：要使Xamarin开心（如注释中所述），请将该File.ReadLines调用替换为对以下助手的调用：
static IEnumerable<string> ReadLines(string path)
{
var sr = new StreamReader(Assets.Open(path));
try
{
string line;
while ((line = sr.ReadLine()) != null)
yield return line;
}
finally { sr.Dispose(); }
}
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