SqlServer中Geography的使用

地理空间数据类型 geography 是作为 SQL Server 中的 .NET 公共语言运行时 (CLR) 数据类型实现的。 此类型表示圆形地球坐标系中的数据。 geography 数据类型存储椭球体（圆形地球）数据，如 GPS 纬度和经度坐标SQL Server 。 SQL Server 支持 geography 空间数据类型的一组方法。 这些方法包括开放地理空间信息联盟 (OGC) 标准和对该标准的一组 Microsoft 扩展所定义的 geography 方法。

--总表面积
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STArea()

--二进制（WKB）表示形式
SELECT geography::STGeomFromText('LINESTRING( -122.360 47.656, -122.343 47.656)', 4326).STAsBinary()

--WKT表示形式
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STAsText()

--缓冲区
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STBuffer(1)

--返回指定的曲线
SELECT geography::STGeomFromText('COMPOUNDCURVE (CIRCULARSTRING (-122.358 47.653, -122.348 47.649, -122.348 47.658), CIRCULARSTRING(-122.348 47.658, -122.358 47.658, -122.358 47.653))',4326).STCurveN(2)

--圆弧线段的多边形近似值
SELECT geography::STGeomFromText('CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653)',4326).STCurveToLine()

--差集
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STDifference(geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326))

--最大维度
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STDimension()

--是否不相联
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STDisjoint(geography::STGeomFromText('POINT( -122.343 47.656)', 4326))

--距离
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STDistance(geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326))

--终点
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STEndPoint()

--判断是否相等
SELECT geography::STGeomFromText('GEOMETRYCOLLECTION(POLYGON((-122.368 47.658, -122.338 47.649, -122.338 47.658, -122.368 47.658, -122.368 47.658)), LINESTRING(-122.360 47.656, -122.343 47.656), POINT (-122.35 47.656))', 4326).STEquals(geography::STGeomFromText('POLYGON((-122.368 47.658, -122.338 47.649, -122.338 47.658, -122.368 47.658, -122.368 47.658))', 4326))

--查找GeometryCollection中第n个实例
SELECT geography::STGeomFromText('MULTIPOINT(-122.360 47.656, -122.343 47.656)', 4326).STGeometryN(2)

--类型
SELECT geometry::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STGeometryType()

--交集
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STIntersection(geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326))

--判断是否相交
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STIntersects(geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326))

--判断是否闭合
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STIsClosed()

--判断是否为空
SELECT geography::STGeomFromText('POLYGON EMPTY', 4326).STIsEmpty()

--判断是否为有效geography格式
SELECT geography::STGeomFromText('LINESTRING(0 0, 2 2, 1 0)', 4326).STIsValid()

--边长总长度
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STLength()

--一维geography曲线数
SELECT geography::STGeomFromText('COMPOUNDCURVE(CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))',4326).STNumCurves()

--geometry数量
SELECT geography::STGeomFromText('MULTIPOINT((-122.360 47.656), (-122.343 47.656))', 4326).STNumGeometries()

--点数量
SELECT geography::STGeomFromText('GEOMETRYCOLLECTION(CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653) ,CURVEPOLYGON(CIRCULARSTRING(-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653)))', 4326).STNumPoints()

--指定点
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STPointN(2)

--空间参考
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STSrid

--起点
SELECT geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326).STStartPoint()

--余集
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STSymDifference(geography::STGeomFromText('POLYGON((-122.351 47.656, -122.341 47.656, -122.341 47.661, -122.351 47.661, -122.351 47.656))', 4326))

--并集
SELECT geography::STGeomFromText('POLYGON((-122.358 47.653, -122.348 47.649, -122.348 47.658, -122.358 47.658, -122.358 47.653))', 4326).STUnion(geography::STGeomFromText('POLYGON((-122.351 47.656, -122.341 47.656, -122.341 47.661, -122.351 47.661, -122.351 47.656))', 4326))

官方资料：

https://docs.microsoft.com/zh-cn/previous-versions/sql/sql-server-2008/bb933960(v=sql.100)

https://docs.microsoft.com/zh-cn/sql/t-sql/spatial-geography/spatial-types-geography?view=sql-server-ver15

https://desktop.arcgis.com/zh-cn/arcmap/latest/manage-data/using-sql-with-gdbs/a-quick-tour-of-sql-functions-used-with-st-geometry.htm