fragmentImageCRSs.xsd How to encode ImageCRS definitions for WCTS image profile. Primary editor: Arliss Whiteside. Last updated 2005-09-12 Copyright (c) Open Geospatial Consortium (2005) Basic encoding for reference system objects, simplifying and restricting the DefinitionType as needed. The name by which this reference system is identified. Description of a spatial and/or temporal reference system used by a dataset. Set of alterative identifications of this reference system. The first srsID, if any, is normally the primary identification code, and any others are aliases. Comments on or information about this reference system, including source information. An identification of a reference system. Association to a reference system, either referencing or containing the definition of that reference system. Abstract coordinate reference system, usually defined by a coordinate system and a datum. This abstract complexType shall not be used, extended, or restricted, in an Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document. Association to a CRS abstract coordinate reference system, either referencing or containing the definition of that CRS. An identification of a CRS object. The first use of the IdentifierType for an object, if any, is normally the primary identification code, and any others are aliases. The code or name for this Identifier, often from a controlled list or pattern defined by a code space. The optional codeSpace attribute is normally included to identify or reference a code space within which one or more codes are defined. This code space is often defined by some authority organization, where one organization may define multiple code spaces. The range and format of each Code Space identifier is defined by that code space authority. Information about that code space authority can be included as metaDataProperty elements which are optionally allowed in all CRS objects. Remarks about this code or alias. Identifier of the version of the associated codeSpace or code, as specified by the codeSpace or code authority. This version is included only when the "code" or "codeSpace" uses versions. When appropriate, the version is identified by the effective date, coded using ISO 8601 date format. Information about this object or code. Contains text or refers to external text. Description of domain of usage, or limitations of usage, for which this CRS object is valid. A coordinate reference system consists of an ordered sequence of coordinate system axes that are related to the earth through a datum. A coordinate reference system is defined by one datum and by one coordinate system. Most coordinate reference system do not move relative to the earth, except for engineering coordinate reference systems defined on moving platforms such as cars, ships, aircraft, and spacecraft. For further information, see OGC Abstract Specification Topic 2. Coordinate reference systems are commonly divided into sub-types. The common classification criterion for sub-typing of coordinate reference systems is the way in which they deal with earth curvature. This has a direct effect on the portion of the earth's surface that can be covered by that type of CRS with an acceptable degree of error. The exception to the rule is the subtype "Temporal" which has been added by analogy. Association to a coordinate reference system, either referencing or containing the definition of that reference system. An engineering coordinate reference system applied to locations in images. Image coordinate reference systems are treated as a separate sub-type because a separate user community exists for images with its own terms of reference. Association to the Cartesian coordinate system used by this CRS. Association to the oblique Cartesian coordinate system used by this CRS. Association to the image datum used by this CRS. Association to an image coordinate reference system, either referencing or containing the definition of that reference system. Basic encoding for coordinate system axis objects, simplifying and restricting the DefinitionType as needed. The name by which this coordinate system axis is identified. Definition of a coordinate system axis. Set of alternative identifications of this coordinate system axis. The first axisID, if any, is normally the primary identification code, and any others are aliases. Comments on or information about this coordinate system axis, including data source information. An identification of a coordinate system axis. The abbreviation used for this coordinate system axis. This abbreviation can be used to identify the ordinates in a coordinate tuple. Examples are X and Y. The codeSpace attribute can reference a source of more information on a set of standardized abbreviations, or on this abbreviation. Direction of this coordinate system axis (or in the case of Cartesian projected coordinates, the direction of this coordinate system axis at the origin). Examples: north or south, east or west, up or down. Within any set of coordinate system axes, only one of each pair of terms can be used. For earth-fixed CRSs, this direction is often approximate and intended to provide a human interpretable meaning to the axis. When a geodetic datum is used, the precise directions of the axes may therefore vary slightly from this approximate direction. Note that an EngineeringCRS can include specific descriptions of the directions of its coordinate system axes. For example, the path of a linear CRS axis can be referenced in another document, such as referencing a GML feature that references or includes a curve geometry. The codeSpace attribute can reference a source of more information on a set of standardized directions, or on this direction. Identifier of the unit of measure used for this coordinate system axis. The value of this coordinate in a coordinate tuple shall be recorded using this unit of measure, whenever those coordinates use a coordinate reference system that uses a coordinate system that uses this axis. Association to a coordinate system axis, either referencing or containing the definition of that axis. Basic encoding for coordinate system objects, simplifying and restricting the DefinitionType as needed. The name by which this coordinate system is identified. A coordinate system (CS) is the set of coordinate system axes that spans a given coordinate space. A CS is derived from a set of (mathematical) rules for specifying how coordinates in a given space are to be assigned to points. The coordinate values in a coordinate tuple shall be recorded in the order in which the coordinate system axes associations are recorded, whenever those coordinates use a coordinate reference system that uses this coordinate system. This abstract complexType shall not be used, extended, or restricted, in an Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document. Set of alternative identifications of this coordinate system. The first csID, if any, is normally the primary identification code, and any others are aliases. Comments on or information about this coordinate system, including data source information. Ordered sequence of associations to the coordinate system axes included in this coordinate system. An identification of a coordinate system. Association to a coordinate system axis. Association to a coordinate system, either referencing or containing the definition of that coordinate system. A 1-, 2-, or 3-dimensional coordinate system. Gives the position of points relative to orthogonal straight axes in the 2- and 3-dimensional cases. In the 1-dimensional case, it contains a single straight coordinate axis. In the multi-dimensional case, all axes shall have the same length unit of measure. A CartesianCS shall have one, two, or three usesAxis associations. Association to a Cartesian coordinate system, either referencing or containing the definition of that coordinate system. A two- or three-dimensional coordinate system with straight axes that are not necessarily orthogonal. An ObliqueCartesianCS shall have two or three usesAxis associations. Association to an oblique-Cartesian coordinate system, either referencing or containing the definition of that coordinate system. Basic encoding for datum objects, simplifying and restricting the DefinitionType as needed. The name by which this datum is identified. A datum specifies the relationship of a coordinate system to the earth, thus creating a coordinate reference system. A datum uses a parameter or set of parameters that determine the location of the origin of the coordinate reference system. Each datum subtype can be associated with only specific types of coordinate systems. This abstract complexType shall not be used, extended, or restricted, in an Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document. Set of alternative identifications of this datum. The first datumID, if any, is normally the primary identification code, and any others are aliases. Comments on this reference system, including source information. An identification of a datum. Description, possibly including coordinates, of the point or points used to anchor the datum to the Earth. Also known as the "origin", especially for engineering and image datums. The codeSpace attribute can be used to reference a source of more detailed on this point or surface, or on a set of such descriptions. - For a geodetic datum, this point is also known as the fundamental point, which is traditionally the point where the relationship between geoid and ellipsoid is defined. In some cases, the "fundamental point" may consist of a number of points. In those cases, the parameters defining the geoid/ellipsoid relationship have been averaged for these points, and the averages adopted as the datum definition. - For an engineering datum, the anchor point may be a physical point, or it may be a point with defined coordinates in another CRS. When appropriate, the coordinates of this anchor point can be referenced in another document, such as referencing a GML feature that references or includes a point position. - For an image datum, the anchor point is usually either the centre of the image or the corner of the image. - For a temporal datum, this attribute is not defined. Instead of the anchor point, a temporal datum carries a separate time origin of type DateTime. The time after which this datum definition is valid. This time may be precise (e.g. 1997.0 for IRTF97) or merely a year (e.g. 1983 for NAD83). In the latter case, the epoch usually refers to the year in which a major recalculation of the geodetic control network, underlying the datum, was executed or initiated. An old datum can remain valid after a new datum is defined. Alternatively, a datum may be superseded by a later datum, in which case the realization epoch for the new datum defines the upper limit for the validity of the superseded datum. Association to a datum, either referencing or containing the definition of that datum. An image datum defines the origin of an image coordinate reference system, and is used in a local context only. For more information, see OGC Abstract Specification Topic 2. Specification of the way an image grid is associated with the image data attributes. Reference to a source of information specifying the values and meanings of all the allowed string values for this PixelInCellType. Association to an image datum, either referencing or containing the definition of that datum.