在PostGreSQL、PostGIS的数据库以及C#环境下，openlayer对矢量切片（GeoJson方式）的操作流程

PostGreSQL运用PostGIS函数查询当前切片范围的矢量数据

数据是SHP文件，通过QGIS导入到PostGreSQL数据库

SQL语句参考地址

	SELECT
        row_to_json(fc)
        FROM (
        SELECT
        'FeatureCollection' AS type
        , array_to_json(array_agg(f)) AS features
        FROM (
        SELECT
        'feature' AS type
        , ST_AsGeoJSON(geom)::json as geometry
        , (
        SELECT
        row_to_json(t)
        FROM (
        SELECT
        id,geom --这里填写矢量数据信息的字段（也就是表字段）
        ) AS t
        ) AS properties
        FROM basemap where geom is not null and id in (
		select id FROM basemap
		where st_within(ST_Transform(geom,4326),
		ST_GeomFromText('POLYGON((-180 90,180 90,180 -90,-180 -90,-180 90))',4326) --此几何为当前切片范围两点最大最小值坐标绘制四边形几何
		) = true --查询在切片范围内的矢量数据
		) order by id asc
        ) AS f
        ) AS fc

从数据库中获取当前切片范围内的矢量数据

        /// <summary>
        /// 从数据库中计算获取切片
        /// </summary>
        /// <param name="level"></param>
        /// <param name="x"></param>
        /// <param name="y"></param>
        public JObject CalculateVectorTile1(RequsetParam param)
        {
   
            //定义切片范围值
            double xmin = 0;
            double xmax = 0;
            double ymin = 0;
            double ymax = 0;
            //计算切片对应的几何范围
            switch (param.Project)
            {
   
                case "4326"://平面坐标系
                    TileModel Model4326 = new ESPG4326TileModel();
                    Model4326.GetTileRect(param.zoon, param.x, param.y, out xmin, out xmax, out ymin, out ymax);
                    break;
                case "3857"://墨卡托坐标系
                    TileModel Model3857 = new ESPG3857TileModel();
                    Model3857.GetTileRect(param.zoon, param.x, param.y, out xmin, out xmax, out ymin, out ymax);
                    break;
                default:
                    break;
            }

            #region Sql语句
            string sql = string.Format(@"SELECT
                                        row_to_json(fc)
                                        FROM (
                                        SELECT
                                        'FeatureCollection' AS type
                                        , array_to_json(array_agg(f)) AS features
                                        FROM (
                                        SELECT
                                        'Feature' AS type
                                        , ST_AsGeoJSON(ST_Transform(geom,{5}))::json as geometry
                                        , (
                                        SELECT
                                        row_to_json(t)
                                        FROM (
                                        SELECT
                                        {0} 
                                        ) AS t
                                        ) AS properties
                                        FROM basemap where geom is not null and id in (
		                                select id FROM basemap
		                                where st_within(ST_Transform(geom,{5}),
		                                ST_GeomFromText('POLYGON(({1} {2},{3} {2},{3} {4},{1} {4},{1} {2}))',{5}) 
		                                ) = true 
		                                ) order by id asc
                                        ) AS f
                                        ) AS fc", param.tbName, xmax, ymax, xmin, ymin, param.Project);
            #endregion

            var str = pg_Query(sql);
            JObject jo = (JObject)JsonConvert.DeserializeObject(str);
            if (string.IsNullOrEmpty(jo["features"].ToString()))
            {
   
                jo = null;
            }
            return jo;
        }
        
        /// <summary>
        /// 公共参数
        /// </summary>
        public class RequsetParam {
   
            /// <summary>
            /// 缩放级别
            /// </summary>
            public int zoon {
    get; set; }
            /// <summary>
            /// 当前切片第一位序号
            /// </summary>
            public int x {
    get; set; }
            /// <summary>
            /// 当前切片第二位序号
            /// </summary>
            public int y {
    get; set; }
            /// <summary>
            /// 当前地图坐标系
            /// </summary>
            public string Project {
    get; set; }
            /// <summary>
            /// 表名
            /// </summary>
            public string layerName {
    get; set; }
            /// <summary>
            /// 字段名
            /// </summary>
            public string tbName {
    get; set; }
        }

获取当前切片范围工具类

3857坐标系获取切片范围工具类

using System;
using System.Collections.Generic;
using System.Linq;