空间引用标识符 (SRID)Spatial Reference Identifiers (SRIDs)

适用于:Applies to: 是SQL ServerSQL Server(所有支持的版本)yesSQL ServerSQL Server (all supported versions) 是Azure SQL 数据库Azure SQL DatabaseYesAzure SQL 数据库Azure SQL Database 是Azure SQL 托管实例Azure SQL Managed InstanceYesAzure SQL 托管实例Azure SQL Managed Instance适用于:Applies to: 是SQL ServerSQL Server(所有支持的版本)yesSQL ServerSQL Server (all supported versions) 是Azure SQL 数据库Azure SQL DatabaseYesAzure SQL 数据库Azure SQL Database 是Azure SQL 托管实例Azure SQL Managed InstanceYesAzure SQL 托管实例Azure SQL Managed Instance

每个空间实例都有一个空间引用标识符 (SRID)。Each spatial instance has a spatial reference identifier (SRID). SRID 对应于基于特定椭圆体的空间引用系统,可用于平面球体映射或圆球映射。The SRID corresponds to a spatial reference system based on the specific ellipsoid used for either flat-earth mapping or round-earth mapping.

空间列可包含具有不同 SRID 的对象。A spatial column can contain objects with different SRIDs. 然而,在使用 SQL ServerSQL Server 空间数据方法对数据执行操作时,仅可使用具有相同 SRID 的空间实例。However, only spatial instances with the same SRID can be used when performing operations with SQL ServerSQL Server spatial data methods on your data. 从两个空间数据实例派生的任何空间方法的结果仅在这两个实例具有相同的 SRID(该 SRID 基于相同的用于确定实例坐标的度量单位、数据和投影)时才有效。The result of any spatial method derived from two spatial data instances is valid only if those instances have the same SRID that is based on the same unit of measurement, datum, and projection used to determine the coordinates of the instances. SRID 最常见的度量单位为米或平方米。The most common units of measurement of a SRID are meters or square meters.

如果两个空间实例的 SRID 不相同,则对这两个实例使用 geometrygeography 数据类型方法后的结果将返回 NULL。If two spatial instances do not have the same SRID, the results from a geometry or geography Data Type method used on the instances will return NULL. 例如,若要以下谓词返回非 NULL 结果,两个 geometry 实例( geometry1geometry2)必须具有相同的 SRID:For example, for the following predicate term to return a non-NULL result, the two geometry instances, geometry1 and geometry2, must have the same SRID:

geometry1.STIntersects(geometry2) = 1

备注

空间引用标识系统是由 欧洲石油测绘组 (European Petroleum Survey Group, EPSG) 的标准定义的,它是为绘图、测绘以及大地测量数据存储而开发的一组标准。The spatial reference identification system is defined by the European Petroleum Survey Group (EPSG) standard, which is a set of standards developed for cartography, surveying, and geodetic data storage. 该标准归石油天然气生产商 (OGP) 测绘和定位委员会所有。This standard is owned by the Oil and Gas Producers (OGP) Surveying and Positioning Committee.

另请参阅See Also

空间数据类型概述Spatial Data Types Overview