2 Spatial Data Types and Metadata

The spatial features in Oracle Spatial consist of a set of object data types, type methods, and operators, functions, and procedures that use these types. A geometry is stored as an object, in a single row, in a column of type SDO_GEOMETRY. Spatial index creation and maintenance is done using basic DDL (CREATE, ALTER, DROP) and DML (INSERT, UPDATE, DELETE) statements.

This chapter starts with a simple example that inserts, indexes, and queries spatial data. You may find it helpful to read this example quickly before you examine the detailed data type and metadata information later in the chapter.

• Simple Example: Inserting, Indexing, and Querying Spatial Data
  This topic presents a simple example of creating a spatial table, inserting data, creating the spatial index, and performing spatial queries
• SDO_GEOMETRY Object Type
  With Spatial, the geometric description of a spatial object is stored in a single row, in a single column of object type SDO_GEOMETRY in a user-defined table.
• SDO_GEOMETRY Methods
  The SDO_GEOMETRY object type has methods (member functions) that retrieve information about a geometry object.
• SDO_GEOMETRY Constructors
  The SDO_GEOMETRY object type has constructors that create a geometry object from a well-known text (WKT) string in CLOB or VARCHAR2 format, or from a well-known binary (WKB) object in BLOB format.
• TIN-Related Object Types
  This topic describes the object types related to support for triangulated irregular networks (TINs),
• Point Cloud-Related Object Types
  This topic describes the following object types related to support for point clouds.
• Geometry Examples
  This topic contains examples of many geometry types.
• Geometry Metadata Views
  The geometry metadata describing the dimensions, lower and upper bounds, and tolerance in each dimension is stored in a global table owned by MDSYS (which users should never directly update). Each Spatial user has the following views available in the schema associated with that user.
• Other Spatial Metadata Views
  Oracle Spatial uses the following other metadata views.
• Spatial Index-Related Structures
  This topic describes the structure of the tables containing the spatial index data and metadata.
• Unit of Measurement Support
  Geometry functions that involve measurement allow an optional unit parameter to specify the unit of measurement for a specified distance or area, if a georeferenced coordinate system (SDO_SRID value) is associated with the input geometry or geometries.