oracle 的 SDO_GEOMETRY

元数据定义

 CREATE OR REPLACE TYPE MDSYS.SDO_GEOMETRY          AS OBJECT (

            SDO_GTYPE       NUMBER,

            SDO_SRID        NUMBER,

            SDO_POINT       SDO_POINT_TYPE,

            SDO_ELEM_INFO   SDO_ELEM_INFO_ARRAY,

            SDO_ORDINATES   SDO_ORDINATE_ARRAY,

            MEMBER FUNCTION  GET_GTYPE

            RETURN NUMBER DETERMINISTIC,

            MEMBER FUNCTION  GET_DIMS

            RETURN NUMBER DETERMINISTIC,

            MEMBER FUNCTION  GET_LRS_DIM

            RETURN NUMBER DETERMINISTIC)

   ALTER TYPE SDO_GEOMETRY

   ADD MEMBER FUNCTION GET_WKB RETURN BLOB DETERMINISTIC,

   ADD MEMBER FUNCTION GET_WKT RETURN CLOB DETERMINISTIC,

   ADD MEMBER FUNCTION ST_CoordDim RETURN SMALLINT DETERMINISTIC,

   ADD MEMBER FUNCTION ST_IsValid RETURN INTEGER DETERMINISTIC,

   ADD CONSTRUCTOR FUNCTION SDO_GEOMETRY(wkt IN CLOB,

             srid IN INTEGER DEFAULT NULL) RETURN SELF AS RESULT,

   ADD CONSTRUCTOR FUNCTION SDO_GEOMETRY(wkt IN VARCHAR2,

             srid IN INTEGER DEFAULT NULL) RETURN SELF AS RESULT,

   ADD CONSTRUCTOR FUNCTION SDO_GEOMETRY(wkb IN BLOB,

             srid IN INTEGER DEFAULT NULL) RETURN SELF AS RESULT

   CASCADE

创建表

create table test_geom(id int,geom MDSYS.SDO_GEOMETRY)

使用wkt插入表

insert into test_geom(id,geom) values(2,SDO_GEOMETRY('point(116.6 24.343)',4326))

查看空间数据的wkt

select a.geom.GET_WKT() from test_geom a

SDO_SRID定义了空间坐标参考系统。如果SDO_SRID为null，则没有指定坐标系统，如果SDO_SRID不为null，那么它的值必须在在MDSYS.CS_SRS 表中的 SRID 列有对应的值，而且它的值必须插入USER_SDO_GEOM_METADATA视图中。MDSYS.CS_SRS 表参考 图2

MDSYS.CS_SRS表
列名	类型	列名描述
CS_NAME	VARCHAR2(68)	坐标系统名称
SRID	NUMBER(38)	空间参考ID，为唯一值。1-999999为spatial使用的空间参考，1000000以后为用户自定义
AUTH_SRID	NUMBER(38)	可选的SRID，是个外键。另一个坐标系统的SRID
AUTH_NAME	VARCHAR2(256)
WKTEXT	VARCHAR2(2046)
CS_BOUNDS	MDSYS.SDO_GEOMETRY

select *from MDSYS.CS_SRS，居然没有3857

计算两点间的距离

 declare

   v_point SDO_GEOMETRY;

   v_ret   number;

 begin

   v_point := SDO_GEOMETRY('point(114.6 12.343)',4326);

   select SDO_GEOM.SDO_DISTANCE(a.geom, v_point, 0.005)

   into v_ret

   from test_geom a

   where id=2;

   dbms_output.put_line(v_ret);

 end;

参考帮助

http://docs.oracle.com/database/121/SPATL/toc.htm

http://docs.oracle.com/cd/B28359_01/appdev.111/b28400/sdo_sql_mm.htm#SPATL025

http://docs.oracle.com/cd/B28359_01/appdev.111/b28400/sdo_objgeom.htm#SPATL120