GML 3.2.1 change request - Correct grid cell terms

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Open Geospatial Consortium

OGC Document 08-080

CR-Form-v3

CHANGE REQUEST

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 Current version:

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Proposed change affects:  AS Imp Spec X Best Practices Paper Other

Title:  GML 3.2.1 change request - Correct grid cell terms

Source:  Arliss Whiteside, Abstract Specification Topic 2 change request OGC 08-010r1

Work item code:  Date:  2008-07-29

Category:  C

Use one of the following categories:

F (Critical correction)

A (corresponds to a correction in an earlier release)

B (Addition of feature),

C (Functional modification of feature)

D (Editorial modification)

Reason for change:  Abstract Specification Topic 2 change request OGC 08-010r1 has corrected the terms for “grid cell” in Tables 33, 39, and 40 to be consistent with ISO 19123 terms. Now the corresponding changes need to be made in GML 3.2.1.

Summary of change:  Correct descriptions of ImageDatum and pixelInCell XML elements

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08-080

Consequences if  not approved:

Significant discrepancy between GML 3.2.1 and corrected Abstract Specification Topic 2

Clauses affected:  11.5.4.3, 11.5.4.4, datums.xsd

Other specs  X Other core specifications  GML 3.1.1, GML 3.1.1 grid CRSs profile, WCS 1.1

Affected: Abstract specifications

X Best Practices Papers Definition identifier URNs in OGC namespace [OGC 07-092r1] Supporting Doc. 

Other comments: 

Status 

Disposition 

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08-080

Edit Clauses 11.5.4.3 and 11.5.4.4 of OGC 07-036 as follows:

12.5.4.3 ImageDatum

</extension> </complexContent> </complexType>

gml:ImageDatum defines the origin of an image coordinate reference system, and is used in a local context only. For an image datum, the anchor definition is usually either the centre of the image or the corner of the image, as indicated by the anchorDefinition. As indicated by the pixelInCell, the exact origin may be at a grid point (the centre of a pixel or the corner of a grid cell). However, the exact origin may alternately be the centre of a grid cell (half way between grid points or the centres of pixels). For more information, see ISO 19111:2007, B.3.5.

12.5.4.4 pixelInCell

gml:pixelInCell is a specification of the way an image coverage grid is associated with the image data

coverage range (pixel) valuesattributes. The required codeSpace attribute shall reference a source of information specifying the values and meanings of all the allowed string values for this property.

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08-080

Edit fragment of the datums.xsd file for GML 3.2.1 as follows:

<documentation>gml:ImageDatum defines the origin of an image coordinate reference system, and is used in a local context only. For an image datum, the anchor definition is usually either the centre of the image or the corner of the image, as indicated by the anchorDefinition. As indicated by the pixelInCell, the exact origin may be at a grid point (the centre of a pixel or the corner of a grid cell). However, the exact origin may alternately be the centre of a grid cell (half way between grid points or the centres of pixels). For more information, see ISO 19111 B.3.5.</documentation>

</annotation> </element>

</extension> </complexContent> </complexType>

<documentation>gml:pixelInCell is a specification of the way an image coverage grid is associated with the image data coverage range (pixel) valuesattributes. The required codeSpace attribute shall reference a source of information specifying the values and meanings of all the allowed string values for this property.</documentation>

</annotation> </element>