Spatial Reference System Identifier

SRID, the Spatial Reference IDentifier, specifies the coordinate system for a geometric object in GIS systems.

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. This standard is owned by the Oil and Gas Producers (OGP) Surveying and Positioning Committee.

A Coordinate Reference System typically consists of things like; Point of Origin (eg: Greenwich or Equator), Scale (Degrees, Metres, Miles). As the world is not a perfect sphere it is challenging to create a coordinate system that is a perfect match for all points on the globe. Each SRID refers to a different set of rules which attempt to solve that problem. A widely used reference system is WGS84

(A quick snippet from Oracle[1]):
The MDSYS.CS_SRS reference table contains over 900 rows, one for each valid coordinate system.

Note:
You should probably not modify, delete, or add any information in the MDSYS.CS_SRS table. If you plan to add any user-defined coordinate systems, be sure to use SRID values of 1000000 (1 million) or higher, and follow the guidelines in Section 5.5.

SRID Values
- 8307 - WGS 84 longitude/latitude