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INTRODUCTION
Oracle Spatial, an option for Oracle Database 10g Enterprise Edition, includes advanced spatial capabilities to support GIS applications, location-based services, and enterprise spatial information systems. Oracle Spatial extends the core location features included in every Oracle database with Oracle Locator.1 Its advanced data manipulation and spatial analysis features include buffer generation, spatial aggregates, area and length calculations, and linear referencing. The first release of Oracle Spatial 10g introduced a GeoRaster datatype to store and manage image and gridded raster data and metadata, network and topology data models, geocoding and routing engines, and spatial analysis and mining functions. These significant new capabilities address business-critical requirements of the public sector, defense, logistics, energy exploration, business geographics, and life sciences domains. The second release of Oracle Spatial 10g introduces eLocation Quick Start, a set of Java APIs for quick and easy deployment of mapping, geocoding, and routing services, and enhances features introduced in the first release. Combined with the performance, scalability, and security of Oracle Database 10g, Oracle Spatial 10g is the most advanced spatial database platform available for enterprise class deployments.
In general, this white paper describes those features included only with Oracle Spatial, but does not cover Oracle Locator features in depth. 2
SPATIAL FUNCTIONS
Oracle Spatial provides functions that perform calculations on geometries, such as area of a polygon and length or perimeter of a geometry. These functions can be used, for example, to determine the total area of all counties around Passaic County, length of an interstate highway, or length of a state border.
Oracle Spatial functions can also generate new geometries such as buffers, unions, intersections, and more. They can be used, for example, to define sales regions by creating a 5 mile buffer around all sales offices, find the geometry representing the union of two sales regions, or find the intersection between two sales regions.
WHOLE EARTH GEOMETRY MODEL FOR GEODETIC COORDINATE SUPPORT
A whole Earth geometry model takes into account the curvature of the Earth’s surface when performing calculations on geodetic data. Thus, Oracle Spatial functions return accurate lengths and areas for both projected and geodetic data. Oracle supports over 30 of the most commonly used distance and area units, e.g. foot/square foot, meter/square meter, kilometer/square kilometer, and so on.
LINEAR REFERENCING SUPPORT
Oracle Spatial supports the storage of "measurement" information associated with a linear geometry. This allows many attributes or events to be associated with a specified segment on a linear geometry. Attributes or events are stored in tables separately from the geometry, and the geometry does not have to be duplicated in the attribute tables. Linear referencing is often used by departments of transportation, to model roads or railroads and their attributes; utilities, to model oil or gas pipes and their attributes; and telecommunications providers.
Functions to manipulate linear referenced geometries are also included, e.g. clipping a piece of a linear feature, concatenating a linear feature, and splitting a linear feature.
SPATIAL AGGREGATES
SQL has long had aggregate functions, which are used to aggregate the results of a SQL query. Spatial aggregate functions operate on a set of geometries rather than just one or two geometries. An aggregate function performs a specified aggregate operation on a set of input geometries, and returns a single geometry object. For example, the following statement returns the state boundary of Tennessee generated from all of the counties in Tennessee:
select sdo_aggr_union(sdoaggrtype(geom,0.5)) state from geod_counties where state_abrv='TN';Other supported aggregate functions include union, centroid, and convex hull; users can also define other aggregate functions. The use of spatial aggregates improves performance and simplifies coding.
GEORASTER SUPPORT (ENHANCED FOR 10G RELEASE 2)
Oracle Spatial includes a data type that natively manages georeferenced raster imagery (satellite imagery, remotely sensed data, gridded data) in Oracle Database 10g. The GeoRaster feature of Oracle Spatial provides georeferencing of imagery; XML schema for metadata management; and basic operations like pyramiding, tiling, and interleaving. Applications in environmental management, defense/homeland security, energy exploration, and satellite image portals will all benefit from this powerful functionality.
New in 10g Release 2: GeoRaster now supports industry standard compression techniques for raster (image and cell-based, or "grid") data, including the JPEG baseline (lossy) and DEFLATE (lossless) standards. Other proprietary compression techniques are supported through third party plugins. All GeoRaster functions that can be performed on uncompressed GeoRaster objects can be performed on compressed objects. Remote sensing imagery results in very large data sets, growing at the rate of a terabyte or more per day. The capability to store and manage these images in compressed form is a key requirement for users and DBAs alike. Customers save money on storage costs when image sizes are reduced by up to 80 percent. This is essential for defense/security, agricultural, and environmental monitoring applications.
For more information about GeoRaster, please refer to separate white papers at www.oracle.com/technology/products/spatial.
NETWORK DATA MODEL (ENHANCED FOR 10G RELEASE 2)
A data model is provided to store network (graph) structure in Oracle Database 10g. It explicitly stores and maintains connectivity of link-node networks and provides network analysis capability such as shortest path and connectivity analysis. Applications requiring network solutions include transportation, transit, utilities and life sciences (biochemical pathway analysis).
New in 10g Release 2: The network data model now includes: a PL/SQL interface for creating, editing, and analyzing network data; a data modeling enhancement for specifying bidirected links; a function to find the maximum allowable flow from a source to a sink node; the ability to create and apply network constraints; and the ability to specify costs by a PL/SQL function.
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