WWT & VO (was NG of GS & BO standards for JPEG with WCS)

[Jonathan Fay]

// lacking only proper astronomical projections.

Yes, that is the key. Shoehorning full sky astronomy data into the wrong projection leads to some very bad consequences, like major issues near the poles.

The key to getting good quality and high speed across the sky is the projection, the equirectangular projections used for full earth maps were just not going to go the distance for astronomy.

Someone once said the adequate is the enemy of the excellent. For astronomy we need to take a stand for full functionality and not be bullied by the GIS community into adopting something that is not suitable for good astronomy visualization, when we can have better.

We need to provide the input to the standards committees to make sure that future updates to standards incorporate astronomy's unique requirements.


Jonathan

-----Original Message-----
From: Alberto Conti [mailto:aconti at stsci.edu]
Sent: Friday, January 18, 2008 10:34 AM
To: Doug Tody
Cc: Jonathan Fay; Pierre Fernique; interop at ivoa.net; Brian McLean; Antonio Volpicelli
Subject: Re: WWT & VO (was NG of GS & BO standards for JPEG with WCS)

>
> One is the OpenGIS Web Map Service (WMS), which is designed for rapid
> remote visualization of graphical data.  With the addition of some
> astronomy oriented projections this could work well for graphical
> data from astronomy.  Unlike SIA, WMS does not require a prior query
> for data access, and instead allows direct access at the pixel level
> to seamless, wide area graphical imagery.
>
At STScI, Antonio Volpicelli, Brian McLean and I have been
experimenting on this for some time now.
It turns our that GoogleSky can "hook" directly onto WMS servers. I
assume WWT can/will be able to do that as well, but I don't know.

We have built a full sky map of GALEX data that drives our in-browser
map application (http://mastmap.stsci.edu/galex/). The same data is
fed to GoogleSky. We had a poster at the AAS on this (047.28) Web
Mapping Services Technology and Astronomical Data (http://
www.abstractsonline.com/viewer/SearchResults.asp)

WMS seems to be a rather nice framework, lacking only proper
astronomical projections.

Ciao,
Alberto

>
>
> On Thu, 17 Jan 2008, Jonathan Fay wrote:
>
>> As far as WWT we are planning to document all our data access
>> interfaces, and open them up some time after we go live pending
>> legal review.
>> We have a cutout service, a high-speed tile service, and a
>> reprojection/compositing service that are currently used internal
>> to WWT that may be opened up as the interfaces stabilize and we
>> confirm the legal status on the data to be served.
>>
>> The reason they exist, rather than hit the VO sources directly is
>> they are highly tuned for large scale visualization across the
>> sky. No current VO service is designed to service that need, so it
>> was necessary for us to implement that service, as well as a new
>> projection to allow full 3d sky access efficiently without
>> singularities. The full sky tile sets are meant to be reprojected
>> with 3d hardware, a software reprojection is necessary for
>> integration of them into 2d imaging applications, thus our cutout
>> and reprojection service.
>>
>> It may take a while for external access to get rolling on this
>> given the new projections, but the cutout server one it is
>> released should be useful for applications fairly quickly as in
>> gives a TAN projection back as JPEG or PNG image, and won't
>> require reprojection for display.
>>
>> Most of this data is sourced from VO sites thru the VO interfaces,
>> but we reproject and tile as necessary to make it scale well. For
>> instance Hubble publishes press release images thru a SIA query
>> and VO Table. Some of which are 16k x 16k and over half a
>> gigabyte. These images are beautiful, but too large for public
>> download. They must be turned into tiled multi-res pyramids to be
>> served on mass scale efficiently. Other VO services had full sky
>> data, but the data must be projected into a tiles multi-res mosaic
>> for visualization. That operation is not real-time friendly, but
>> once that work has been done the result is a useful service that
>> should (and will be) made available to others to use.
>>
>> Related to your other question is that WWT will also natively open
>> AVM encoded images (currently a IVOA note) and display them
>> directly in the sky. The last details of V1.1 of the proposed
>> standard were hashed out at a meeting at AAS last week. Spitzer,
>> Chandra and Hubble images are all going to be encoded with AVM,
>> and many already are.
>>
>> WWT Pro, that we are co-developing with Harvard IIC/CFA will be a
>> very rich VO client for interacting with VO images,  catalogs,
>> footprints, events, etc. While it is entirely possible to have all
>> this functionality in the wide release version of WWT, we don't
>> want to overload the existing VO infrastructure.
>>
>> Jonathan Fay
>> Principal Research Software Design Engineer
>> WorldWide Telescope
>> Microsoft Research
>>
>>
>> -----Original Message-----
>> From: owner-interop at eso.org [mailto:owner-interop at eso.org] On
>> Behalf Of Pierre Fernique
>> Sent: Thursday, January 17, 2008 12:17 AM
>> To: interop at ivoa.net
>> Subject: Re: next generation of Sky in Google Earth
>>
>>
>> Dear VO members,
>>
>> I would like to bring the discussion to another point related to
>> the VO
>> and Google Sky/WWT.
>>
>> I would like to ask to Google sky team and Microsoft WWT team if
>> it is
>> possible to create my own client accessing their image data base. For
>> instance, if I want to add a dedicated Aladin layer displaying the
>> HTM
>> sky background images from Microsoft data base, or the sector base
>> sky
>> background images from Google, could I ? 1) Is there open
>> standards for
>> that and I can develop my own client ? 2) Could I have to plug a
>> kind of
>> proprietary libraries in Aladin ? 3) Or perhaps it is not possible at
>> all (technically ? strategically ? no documented ?) Obviously, the
>> first
>> solution will be the best for my VO point of view.
>>
>> I really appreciate to offer to Aladin users these astronomical data.
>> Exactly in a symetric way that WWT and Google Sky use Simbad opened
>> standards (object resolver, ...), or VizieR catalog access, and
>> other VO
>> access..
>>
>> Pierre Fernique
>>

Dr Alberto Conti
Community Missions Office
Space Telescope Science Institute
contact | tel: 410-338-4534 | aim: wscience