Module org.opengis.geoapi

Package org.opengis.referencing.datum

Interface ImageDatum

All Superinterfaces:

Datum, IdentifiedObject

@Deprecated(since="3.1")
@UML(identifier="CD_ImageDatum",
     specification=ISO_19111,
     version=2007)
public interface ImageDatum
extends Datum

Deprecated.

Replaced by EngineeringDatum as of ISO 19111:2019.

Defines the origin of an image coordinate reference system. An image datum is used in a local context only. For an image datum, the anchor point is usually either the centre of the image or the corner of the image. The image datum definition applies regardless of whether or not the image is georeferenced. Georeferencing is performed through a transformation of image CRS to geodetic or projected CRS. The transformation plays no part in the image datum definition.

The image pixel grid is defined as the set of lines of constant integer coordinate values. The term "image grid" is often used in other standards to describe the concept of Image CRS. However, care must be taken to correctly interpret this term in the context in which it is used. The term "grid cell" is often used as a substitute for the term "pixel".

The grid lines of the image may be associated in two ways with the data attributes of the pixel or grid cell. The data attributes of the image usually represent an average or integrated value that is associated with the entire pixel. An image grid can be associated with this data in such a way that the grid lines run through the centres of the pixels. The cell centres will thus have integer coordinate values. In that case the attribute "pixel in cell" will have the value "cell centre". Alternatively, the image grid may be defined such that the grid lines associate with the cell or pixel corners rather than the cell centres. The cell centres will thus have noninteger coordinate values, the fractional parts always being 0.5. The attribute "pixel in cell" will now have the value "cell corner". This difference in perspective has no effect on the image interpretation, but is important for coordinate transformations involving this defined image.

Since:

1.0

See Also:

• DatumAuthorityFactory.createImageDatum(String)
• DatumFactory.createImageDatum(Map, PixelInCell)

Field Summary

Fields inherited from interface org.opengis.referencing.datum.Datum

ANCHOR_DEFINITION_KEY, ANCHOR_EPOCH_KEY, ANCHOR_POINT_KEY, CONVENTIONAL_RS_KEY, DOMAIN_OF_VALIDITY_KEY, PUBLICATION_DATE_KEY, REALIZATION_EPOCH_KEY, SCOPE_KEY

Fields inherited from interface org.opengis.referencing.IdentifiedObject

ALIAS_KEY, DOMAINS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY

Method Summary

Modifier and Type	Method	Description
PixelInCell	getPixelInCell()	Deprecated. Specification of the way the image grid is associated with the image data attributes.

Methods inherited from interface org.opengis.referencing.datum.Datum

getAnchorDefinition, getAnchorEpoch, getAnchorPoint, getConventionalRS, getDomainOfValidity, getPublicationDate, getRealizationEpoch, getScope

Methods inherited from interface org.opengis.referencing.IdentifiedObject

getAlias, getDomains, getIdentifiers, getName, getRemarks, toWKT

Method Details

getPixelInCell

@UML(identifier="pixelInCell",
     obligation=MANDATORY,
     specification=ISO_19111)
PixelInCell getPixelInCell()

Deprecated.

Specification of the way the image grid is associated with the image data attributes.

Returns:

the way image grid is associated with image data attributes.