SDO_GEOMETRY数据类型定义，包括村村所有类型的集合体(点，线，多边形)。(重点)

使用索引引擎和几何引擎进行查询和分析。(重点)

使用位置编码引擎实现位置使能。

高级空间索引(包括路由和网络分析)。(重点)

把 Geometry转换为 GML(Geography Markup Language)文档
select TO_CHAR(SDO_UTIL.TO_GMLGEOMETRY(geoloc)) from rbeijing r where r.id=’59552500066′

(5)、计算空间实体的几何体函数

SDO_GEOM Package (Geometry)
This chapter contains descriptions of the geometry-related PL/SQL subprograms in the SDO_GEOM package, which can be grouped into the following categories:
Relationship (True/False) between two objects: RELATE, WITHIN_DISTANCEValidation: VALIDATE_GEOMETRY_WITH_CONTEXT, VALIDATE_LAYER_WITH_CONTEXT
Single-object operations: SDO_ARC_DENSIFY, SDO_AREA, SDO_BUFFER, SDO_CENTROID, SDO_CONVEXHULL, SDO_LENGTH, SDO_MAX_MBR_ORDINATE, SDO_MIN_MBR_ORDINATE, SDO_MBR, SDO_POINTONSURFACETwo-object operations: SDO_DISTANCE, SDO_DIFFERENCE, SDO_INTERSECTION, SDO_UNION,
SDO_XOR

SDO_GEOM.RELATE()——检查两个几何体对象，确定它们之间的空间关系 
SDO_GEOM.SDO_AREA()——计算两维几何多边形的面积 
SDO_GEOM.SDO_DISTANCE()——计算两个几何对象间的距离，距离为两个集合对象上距离最近的点或线段之间的距离。 
SDO_GEOM.SDO_LENGTH——计算一个几何体对象的长度或周长 
SDO_GEOM.WITH_DISTANCE——确定两个空间对象是否位于给定的欧氏距离以内 
SDO_GEOM.SDO_CENTROID()——确定几何实体的重心 
SDO_GEOM.SDO_DIFFERENCE()——计算两个几何体进行差运算的结果几何体 
SDO_GEOM.SDO_INTERSECTION——返回两个几何实体的交集结果 

(6)空间操作符(Spatial Operators)
This chapter describes the operators that you can use when working with the spatial object data type. For an overview of spatial operators, including how they differ from 
spatial procedures and functions
SDO_FILTER Specifies which geometries may interact with a given geometry.
SDO_JOIN Performs a spatial join based on one or more topological relationships.
SDO_NN Determines the nearest neighbor geometries to a geometry.
SDO_NN_DISTANCE Returns the distance of an object returned by the SDO_NN operator.
SDO_RELATE Determines whether or not two geometries interact in a specified way. (See also Table 11–2 for convenient alternativ operators for performing specific mask value operations.)
SDO_WITHIN_DISTANCE Determines if two geometries are within a specified distanc from one another.
SDO_ANYINTERACT Checks if any geometries in a table have the ANYINTERA topological relationship with a specified geometry.
SDO_CONTAINS Checks if any geometries in a table have the CONTAINS topological relationship with a specified geometry. mdsys.sdo_contains(d.geoloc,n.geoloc)=’TRUE’ 表示d 包含 n
SDO_COVEREDBY Checks if any geometries in a table have the COVEREDBY topological relationship with a specified geometry.
SDO_COVERS Checks if any geometries in a table have the COVERS topological relationship with a specified geometry.
SDO_EQUAL Checks if any geometries in a table have the EQUAL  topological relationship with a specified geometry.
SDO_INSIDE Checks if any geometries in a table have the INSIDE  topological relationship with a specified geometry.
SDO_ON Checks if any geometries in a table have the ON topological  relationship with a specified geometry.
SDO_OVERLAPBDYDISJOINT  Checks if any geometries in a table have the 
OVERLAPBDYDISJOINT topological relationship with a  specified geometry.
SDO_OVERLAPBDYINTERSECT Checks if any geometries in a table have the 
OVERLAPBDYINTERSECT topological relationship with a  specified geometry.
SDO_OVERLAPS Checks if any geometries in a table overlap (that is, have the 
OVERLAPBDYDISJOINT or OVERLAPBDYINTERSECT  topological relationship with) a specified geometry.
SDO_TOUCH Checks if any geometries in a table have the TOUCH  topological relationship with a specified geometry.

(7)、几何函数和空间操作符的区别

patial Operators, Procedures, and Functions
Spatial operators, such as SDO_FILTER and SDO_RELATE, provide optimumperformance because they use the spatial index. (Spatial operators require that the
geometry column in the first parameter have a spatial index defined on it.) Spatialoperators must be used in the WHERE clause of a query. The first parameter of any
operator specifies the geometry column to be searched, and the second parameterspecifies a query window. If the query window does not have the same coordinate
system as the geometry column, Spatial performs an implicit coordinate systemtransformation. For detailed information about the spatial operators, see Chapter 11.
Spatial procedures and functions are provided as subprograms in PL/SQL packages,such as SDO_GEOM, SDO_CS, and SDO_LRS. These subprograms do not require that a spatial index be defined, and they do not use a spatial index if it is defined. These subprograms
can be used in the WHERE clause or in a subquery. If two geometries a input parameters to a Spatial procedure or function, both must have the same coordinate system.
The following performance-related guidelines apply to the use of spatial operators,procedures, and functions:
If an operator and a procedure or function perform comparable operations, and if the operator satisfies your requirements, use the operator. For example, unless you
need to do otherwise, use SDO_RELATE instead of SDO_GEOM.RELATE, and use SDO_WITHIN_DISTANCE instead of SDO_GEOM.WITHIN_DISTANCE.
空间操作提供最佳性能，因为使用了空间索引。而且空间操作只能被使用在WHERE后面。如果两个参数的坐标系统不一致空间执行隐式坐标系统转换。
空间过程和函数提供子在PL / SQL包,如sdo几何学,sdo cs,sdo中。 这些子程序不需要那空间索引被定义,并且他们不使用空间索引定义。这些子可以用在WHERE子句或子查询。如果两个图形一个输入参数空间过程或函数,都必须有相同的坐标系统。
如果一个操作符和一个过程或函数都能实现对应的操作,如果操作符能满足你的要求,使用操作符。比如SDO_RELATE instead of SDO_GEOM. RELATE，SDO_WITHIN_DISTANCE instead of SDO_GEOM.WITHIN_DISTANCE

参考：http://www.cnblogs.com/lanzi/archive/2010/12/30/1922249.html

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