使用 C# 从 Well Known Text 创建 GeoJSON 输出

Question

我正在尝试创建类似于此处描述的 GeoJSON 格式的 JSON 输出：http://geojson.org/geojson-spec.html

特别是，我有从我的数据源以文本格式返回的文本，我想将我的 DTO 转换为 JSON，格式如下我的评论所示。我遇到的主要问题是尝试创建没有属性名称的坐标数组 [[ ... ]]。

代码：

/*

                Geometry Text Format from database:  POLYGON ((319686.3666000003 7363726.7955, 319747.05190000031 7363778.9233, 319700.78849999979 7363832.7814, 319640.10329999961 7363780.6536, 319686.3666000003 7363726.7955))

                And we want format:
                "geometry": {
                    "type": "Polygon",
                    "coordinates": [[
                        [319686.3666000003, 7363726.795],
                        [319747.0519000003, 7363778.9233],
                        [319700.78849999979, 7363832.7814],
                        [319640.10329999961, 7363780.6536],
                        [319686.3666000003, 7363726.795]
                    ]]
                }

                */


                // Strip out everything except the coordinates
                var coordRawText = myWkt.Replace("POLYGON ((", "");
                coordRawText = coordRawText.Replace("))", "");
                coordRawText = coordRawText.Replace(", ", ",");

                // Seperate coordinates to iterate through
                var coordsArray = coordRawText.Split(',');
                var coordsEnumerable = coordsArray.Select(coord => coord.Replace(" ", ","));

                // Build list of coordinates
                var coordsList = new List<CoordinateDto>();
                foreach (var coord in coordsEnumerable)
                {
                    var splt = coord.Split(',');
                    var x = double.Parse(splt[0]);
                    var y = double.Parse(splt[1]);

                    coordsList.Add(new CoordinateDto {X = x, Y = y});
                }

                myDto.Geometry = new GeometryDto
                {
                    Type =  "Polygon",
                    Coordinates = coordsList
                };

以上输出 "almost" 我想要的，但不完全是。输出如下图：

"geometry":{"type":"Polygon","coordinates":[{"x":319686.3666000003,"y":7363726.7955},{"x":319747.05190000031,"y":7363778.9233},{"x":319700.78849999979,"y":7363832.7814},{"x":319640.10329999961,"y":7363780.6536},{"x":319686.3666000003,"y":7363726.7955}]}

我的DTO定义如下：

[DataContract]
public class GeometryDto
{
    [DataMember]
    public string Type { get; set; }

    [DataMember]
    public List<CoordinateDto> Coordinates { get; set; }


}


[DataContract]
public class CoordinateDto
{
    [DataMember]
    public double X { get; set; }

    [DataMember]
    public double Y { get; set; }


}

我曾尝试使用元组而不是坐标 class，但只是插入了 "item1" 和 "item2" 属性名称而不是 "x" 和 "y".

我唯一没有尝试过的是创建我自己的 JSON 转换器？

在此先感谢您的帮助，

亲切的问候，

斯蒂芬

更新解决方案

多亏了这里选择的答案（来自 Dhanuka777）关于多维数组，我找到了一个解决方案，但为了完整性以防它有帮助：

我必须创建一个新的辅助函数（Jon Skeet 的 Create Rectangular Array 函数的略微修改版本，来自此处：How to convert list of arrays into a multidimensional array）

代码解决方案如下图：

/*

                Geometry Text Format from database:  POLYGON ((319686.3666000003 7363726.7955, 319747.05190000031 7363778.9233, 319700.78849999979 7363832.7814, 319640.10329999961 7363780.6536, 319686.3666000003 7363726.7955))

                And we want format:
                "geometry": {
                    "type": "Polygon",
                    "coordinates": [[
                        [319686.3666000003, 7363726.795],
                        [319747.0519000003, 7363778.9233],
                        [319700.78849999979, 7363832.7814],
                        [319640.10329999961, 7363780.6536],
                        [319686.3666000003, 7363726.795]
                    ]]
                }

                */


                // Strip out everything except the coordinates
                var coordRawText = myWkt.Replace("POLYGON ((", "");
                coordRawText = coordRawText.Replace("))", "");
                coordRawText = coordRawText.Replace(", ", ",");

                // Seperate coordinates to iterate through
                var coordsArray = coordRawText.Split(',');
                var coordsEnumerable = coordsArray.Select(coord => coord.Replace(" ", ","));

                // Build list of coordinates
                var coordsList = new List<double[,]>();
                foreach (var coord in coordsEnumerable)
                {
                    var splt = coord.Split(',');
                    var x = double.Parse(splt[0]);
                    var y = double.Parse(splt[1]);

                    coordsList.Add(new[,] {{ x, y }});
                }

                myDto.Geometry = new GeometryDto
                {
                    Type =  "Polygon",
                    Coordinates = CreateRectangularArray(coordsList)
                };

Create Rectangular Array 定义的稍微修改版本如下：

static T[,] CreateRectangularArray<T>(IList<T[,]> arrays)
        {
            // TODO: Validation and special-casing for arrays.Count == 0
            int minorLength = arrays[0].Length;
            T[,] ret = new T[arrays.Count, minorLength];
            for (int i = 0; i < arrays.Count; i++)
            {
                var array = arrays[i];
                if (array.Length != minorLength)
                {
                    throw new ArgumentException
                        ("All arrays must be the same length");
                }
                for (int j = 0; j < minorLength; j++)
                {
                    ret[i, j] = array[0, j];
                }
            }
            return ret;
        }

更新后的GeometryDto如下：

[DataContract]
    public class GeometryDto
    {
        [DataMember]
        public string Type { get; set; }

        [DataMember]
        public double[,] Coordinates { get; set; }


    }

Web API 将使用 Newtonsoft Json 以所需格式序列化对象。

Answer 1

我宁愿使用 Newtonsoft Json 序列化程序来输出它。将坐标定义为二维数组即可。

public class GeometryDto
    {
        public string Type { get; set; }

        public double[,] coordinates { get; set; }            

    }

    class Program
    {
        static void Main()
        {
            var obj = new GeometryDto
            {
                Type = "Polygon",
                coordinates = new double[,] { { 319686.3666000003, 7363726.795 }, { 319747.0519000003, 7363778.9233 }, { 5.3434444, 6.423443 }, { 7.2343424234, 8.23424324 } }                     
            };
            var json = Newtonsoft.Json.JsonConvert.SerializeObject(obj);
            Console.WriteLine(json);
            Console.ReadKey();
        }
    }

从这里获取 Nuget。

输出： {"Type":"Polygon","coordinates":[[319686.3666000003,7363726.795],[319747.05190000031,7363778.9233],...]}

使用 C# 从 Well Known Text 创建 GeoJSON 输出

Creating GeoJSON output from Well Known Text with C#

c#

json

dto

geojson

asp.net-web-api2