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IVOA Simple Image Access Version 2.0
Version 2.0

IVOA Proposed Recommendation 07 July 2014

Interest/Working Group:
Patrick Dowler, Doug Tody, Francois Bonnarel, Ray Plante
Patrick Dowler, Doug Tody


The Simple Image Access protocol (SIA) provides capabilities for the discovery, description, access, and retrieval of multi-dimensional image datasets, including 2-D images as well as datacubes of three or more dimensions. SIA is based upon the Image Data Model (ImageDM), which describes datasets characterized by an N-dimensional, regularly sampled numeric data array, with associated metadata describing the overall multi-dimensional image dataset as well as a separable World Coordinate System (WCS) describing the physical measurement axes of the image. Image datasets with dimension greater than 2 are often referred to as datacubes, cube or image cube datasets and may be considered examples of hypercube or n-cube data. In this document the term "image" refers to general multi-dimensional datasets and is synonymous with these other terms unless the image dimensionality is otherwise specified. SIA provides capabilities for image discovery and access. Discovery and detailed metadata access (using ImageDM) are defined here. The capabilities for drilling down to data files (and related resources) and services for remote access are defined elsewhere, but SIA provides clear and optimised access to these services.

Status of this document

This is an IVOA Proposed Recommendation made available for public review.
It is appropriate to reference this document only as a recommended standard that is under review and which may be changed before it is accepted as a full recommendation.

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