Definitions

The search results will display a list of matching objects, including a selection of values for each object.

Click the object name to see a detailed report of the object.

The top of the page will display a tabular summary of the main parameters. Below is an example.

At the bottom of the page in expandable sections are additional details about the object and its related parameters. This section also contains Actions for exporting or sharing the data.

URL - The url button will open a direct link to the object in a new tab or window.

Print- The print function will create a clean report of the object in a new tab or window. In most browsers use CTRL+P or the browser right-click context menu to print th

GML - This will open a GML definition of the object in a new tab or window.

WKT - This will open a WKT definition of the object in a new tab or window.

See below for more information about an object or parameter.

Object Types

  • Units of Measure

    • Linear Units - Units for measuring straight line, Cartesian distances.

    • Angular Units - Type of units for measuring rotation.

    • Scalar Units - Unit of measure for scale factor.
  • Prime Meridians - The Prime Meridian represents the line of longitude that is designated as 0 degrees.  All other lines of longitude are expressed by the angle by which they deviate from the Prime Meridian.  Together with the equator of an Ellipsoid, the Prime Meridian defines the origin of a Geodetic Coordinate System.  A Prime Meridian is defined by the angle that separates it from the Greenwich Meridian.  

  • Ellipsoids - An Ellipsoid gives a Datum its size and shape.  An Ellipsoid does not have an origin and cannot be used as a base model for coordinates on its own.

  • Datums - A Datum is the base model that maps are built on.  All coordinate systems must have a datum associated with them to be related to any other map.  Without a known datum, coordinates are meaningless.

  • Coordinate Transformations - Coordinate Transformations (Concatenated, Datum, Parametric or Vertical) - Parameters to transform coordinates from one Coordinate System to another.

  • Coordinate Systems (Coordinate Reference Systems) - A Coordinate System is a complete definition needed to express the context of a set of map data.

    • Geodetic Coordinate System - A two or three-dimensional coordinate system defined by an ellipsoid, the equatorial plane of the ellipsoidal and a plane defined along the polar axis (a meridional plane).
    • Geocentric Coordinate System- A geocentric coordinate system is a 3-dimensional coordinate system represented by X,Y,Z coordinates. The origin of the system is the center of the earth.This is also refered to as earth-centered, earth-fixed (ECEF).
    • Projected Coordinate System- A map projection is a systematic transformation of a 3-dimensional coordinate system into locations on a plane (2-dimensional surface). All map projections contain some necessary distortion in order to achieve this. They may preserve different properties, or minimize distortion in particular areas, depending on the purpose of the projection.
  • Point Styles (Coordinate Points) - A Point Style is used to define the orientation of axes used and the type of units used in the system.

  • Areas of Use - Define a geographic area of use for a particular object.

Object Parameters

The results window will display a selection of defining parameters specific to the object type. See below for more information about a parameter.

General Parameters

  • Name - Descriptive name of the object.
  • EPSG Code- Identifier code assigned to the object by the EPSG. Codes are unique by object type.
  • Deprecated - This value will be True if the object has been deprecated. Deprecated objects are not searched by default, and searching deprecated objects must be enabled. Following the EPSG standards, object definitions with errors or that have been superseded are deprecated rather than removed in order to maintain a complete datasource.
  • GML - This button will load an XML definition in Geographic Markup Language.
  • WKT - This button will display Coordinate Reference system or transformations in WKT (Well Known Text) format.
  • Remarks - Additional notes about the object. This may include supplementary information.
  • Revision Date - Date of most recent revision to the object definition.
  • Identifiers - Authority codes linked to the object definition. These are reference codes used to define the object by different authorities.
  • History - this is a history of revisions to the object definition. The history will include things like Authority, Report Date, Reporter and Actions takes to change the object definition.
  • URL- right click on the url button and choose copy url or copy link to save a direct link to the object definition. Some browsers also support CTRL - click to open the object directly in a new browser tab.