Collaborative Page for SIA Interface
The Simple Image Access (SIA) interface defines a protocol for retrieving image data from a variety of multidimensional astronomical image/cube repositories through a uniform interface. The interface is meant to be reasonably simple to implement by service providers. A query defining a multi-parameter query is used to query for candidate images. The service returns a list of candidate datasets formatted as a VOTable. For each candidate image an access reference URL may be used to retrieve the image. Direct client-directed access to a remote image/cube dataset is also provided. Images may be returned in a variety of formats including FITS, other astronomical image formats, and various graphics formats. Referenced images are often computed on the fly, e.g., as cutouts from larger images.
Current SIAV2 Working Draft
The SIAV2 working draft has been split into two closely linked documents, the SIA version 2.0 specification per se, and the Image data model it is based upon. This version of SIA, and the new Image data model, are fully multidimensional and capable of dealing with cube data.
The 2013 SIAV2 working draft has been pretty much completely rewritten to make use of modern (draft) standards such as the
ImageDM,
DALI, and so on. The current (12Aug) draft is complete through the queryData request, although the query response section is still pretty rough. A key element which is not yet included in the draft is the accessData request, used to interactively slice/dice remote cubes. A preliminary description of the data access model behind accessData is given in the
ImageDM working draft.
Older drafts and Related Papers
Since late 2009
SIA V1.0 is now an IVOA Recommendation.
A major update to the SIA interface, SIA V2.0, is in the planning stages. A partial working draft is available at the link above, as well as related analysis papers as noted on this page.
SIA Related IVOA Notes
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DougTody August 2013
VAO Prototyping Effort
The VAO Project is building a prototype SIAv2 service for presentation and demonstration at the Fall 2013 Interop.
More information on the scope and progress of this effort can be found in the
SIA2VAOPrototype page.