c# - 如何从另一个 SqlGeometry 对象获取 SqlGeometry 对象上的最近点？

Question

我有一组线和多边形对象(SqlGeometry 类型)和一个点对象(SqlGeometry 类型)。我们如何从给定的点对象找到每条线上最近的点？是否有任何 API 可以执行此操作？

Answer 1

此处示例展示了使用 SqlGeometry 和 C# 的可能解决方案，不需要 SQL Server:

using System;
using Microsoft.SqlServer.Types;
namespace MySqlGeometryTest
{
    class ReportNearestPointTest
    {
        static void ReportNearestPoint(string wktPoint, string wktGeom)
        {
            SqlGeometry point = SqlGeometry.Parse(wktPoint);
            SqlGeometry geom = SqlGeometry.Parse(wktGeom);
            double distance = point.STDistance(geom).Value;
            SqlGeometry pointBuffer = point.STBuffer(distance);
            SqlGeometry pointResult = pointBuffer.STIntersection(geom);
            string wktResult = new string(pointResult.STAsText().Value);
            Console.WriteLine(wktResult);
        }

        static void Main(string[] args)
        {
            ReportNearestPoint("POINT(10 10)", "MULTIPOINT (80 70, 20 20, 200 170, 140 120)");
            ReportNearestPoint("POINT(110 200)", "LINESTRING (90 80, 160 150, 300 150, 340 150, 340 240)");
            ReportNearestPoint("POINT(0 0)", "POLYGON((10 20, 10 10, 20 10, 20 20, 10 20))");
            ReportNearestPoint("POINT(70 170)", "POLYGON ((110 230, 80 160, 20 160, 20 20, 200 20, 200 160, 140 160, 110 230))");
        }
    }
}

程序输出:

POINT (20 20)
POINT (160 150)
POINT (10 10)
POINT (70 160)