Further Release(s) of VO Desktop software : V1.3.2

As of December 2009, it is unclear how to continue developing the distinct AstroGrid components and tools. However, it is of considerable importance to release one more version, that demonstrates the use of the newly agreed Table Access Protocol (TAP). This hopefully will encourage many more TAP services to be deployed. This page will collect a to-do/wish list, intended to be relatively simple, so we can make the release before Christmas or just after. If anything looks too complicated, we will leave it for another time. As usual the latest testing snapshots can be found at DesktopAstroGridSnapshots.


  • DONE loading from file at ftp address : fixed now (http works fine, and VOSpace does in principle, but we don't have a public VOSpace. Just ignore this for now.)
  • DONE can't edit subscription. This means if you have forgotten where a subscription comes from, you can't find out ! Also, the author of the subscription might eg move file to a different folder and tell colleagues, so editing might make sense.

[Andy : Excellent. Finished.]

Static Lists

  • when you pick "edit", you get only a list of ivo-ids, and they are not even in the same order as when you see them in the resources window. This makes the list very hard to edit - you have to remember the telephone numbers. To add to a static list, you can drag and drop. Why there can't be a "delete resource from list" in the resources pane ? (Or dragging to a trashcan...)
    • It can't be in same order as in the resources window, as the user could have chosen any kind of sorting criteria for the resources window. I could add a 'remove resource from this list' as an item on the popup menu for the resouces table, and as an item on the 'resource' dropdown menu. Of course, this operation would only be available when viewing a static list - would appear as grayed out the rest of the time. This might take a fair bit of replumbing - I'll take a look - but would certainly be easier to implement than dragging to a trashcan -- NoelWinstanley - 2010-01-04
    • DONE done - added 'Edit > Remove selected resources from this list' - works fine.

  • in principle, the edit window could have a little more info... but actually all it does is add and subtract, so if you could delete through the normal resources pane, you maybe wouldn't even need it.
    • The reason the edit window provides so little info is that it would need to retrieve the resouces from the registry before being able to display anything more than the ivorn. Although this would be possible to do, it makes the whole implementation much more complex, and raises all kinds of UI questions - i.e when the user adds a new item to the list, at what point is it checked against the registry? I think it's best just to implement the 'remove resource from this list' operation above. -- NoelWinstanley - 2010-01-04 [Agreed : Andy]

[Andy : This section also finished]

Searching for TAP services

  • DONE in "New Smartlist" Service Capability offered is "/TAP". I note this what the RegQL version wants; "Service Capability=TAP" finds all the STAP services....
    • I've adjusted the display in the service capability to 'TAP', but the RegQL version must stay as /TAP - (RegQL does substring matching, and so the '/' is necessary, but ugly.) -- NoelWinstanley - 2010-01-04
  • DONE Should perhaps be TAP : Table/Database Access (too long ?)
    • Done. A little unsymmetric with SIAP, CONE, which all describe them selves as 'something Service', but it fits ok.

[Andy : All fine. Finished.]

Testing TAP services

  • I find seven available services
  • seem to work ok (haven't checked all thoroughly)
  • when execution complete get button asking to click "OK" which flips back to VO Explorer window... tad annoying/confusing. This window flipping is happening in a few other places too.
    • Wasn't me, guv! This is wonderful java-6 on recent Macs - it's implementation of the system tray seems to add an 'ok' button to popup messages (previous versions just popup the message, and it fades away after time). Vodesktop uses system-tray popups to notify the user when long-running tasks have completed. This used to be fine, but now that the popup messages grab focus and have an 'ok' button, it's much less nice. According to the Javadocs, it's platform-dependent whether the message disappears after some time, requires a click to dismiss, or, as in this case, grabs focus. Great!. question What do you think would be best - leave-as-is, remove systemtray popup mesages altogether, or just remove them for java6 on Mac? -- NoelWinstanley - 2010-01-04
    • The focus switching is really annoying, and an increasing number of people are using Macs. So I think I vote for switching off the system tray pop-up messages. Is there another way to notify users of long-task completion ? --Main.AndyLawrence - 2010-01-07
    • DONE fixed - the popups still occur, but they aren't modal - can continue working without clicking 'OK'. Furthermore, clicking 'OK' only dismisses the message - doesn't cause the current window you're using to lose focus and flip back to the voexplorer.

TAP Action offered in VO Explorer

  • offered query / multi-query / build adql / TAP query
  • in a later version we should rethink all this quite carefully, along with the future of Astroscope
  • but for now "build adql" and "TAP query" are really the same thing from the users point of view, and picking these actions leads to new panes which are ALMOST but not quite identical; much better if there is a single interface for querying databases, regardless of whether they are enabled via TAP or enable via CEA. The user won't care
    • question I think this is an issue with the registration of resources: as long as a single resource is offering both CEA and TAP capabilities, do we need to allow the user to select which to use? - ie. is it important that CEA at present has more functionality (e.g. save to myspace). Note - once all databases move across to TAP, the CEA action won't be presented to the user. We could hurry this along, by not presenting the CEA action if a resource has both CEA and TAP capabilities - what do you think? -- NoelWinstanley - 2010-01-04
    • Yes, I would vote for not presenting the CEA action if a resource has both CEA and TAP. --Main.AndyLawrence - 2010-01-07
    • DONE done.
  • DONE "TAP" is VO jargon. The action should perhaps be "Table/database query" or if there isn't room, just "Table Query"
  • DONE I would then suggest also changing the usual Astroscope related "Query" action to "Position Query" and "Multi-position query".

TAP/Task Runner interface

  • The CEA-related "Build ADQL" and the TAP-related "TAP Query" both lead to the Query-Builder variant of the Task Runner interface. The difference seems to be that the TAP version has some stuff missing - no offer of cone or multi-cone interface, and no choice of saving to cache or VOSpace.

The TAP 1.0 standard doesn't support saving to VOSpace, so we don't offer it. TAP 1.0 has no registry metadata to denote whether a service supports positional parameters (which are optional), so it's not easy to make a UI that covers this cleanly. -- GuyRixon - 2009-12-22

  • As suggested above, there should be only be one interface. Does this give something that the usual astroscope doesn't ? Usually not, but sometimes it does, when a CEA-app contains more than one table that it is possible to cone-search on. Does every TAP service always have a possible conesearch ? At the moment yes, but in the future very often not; the big TAP market might be all those Vizier tables.

So option-1 is to lose the cone and multi-cone stuff completely with the minor loss of choosing which table to cone-search on. Option-2 is to grey-out the cone search stuff where it doesn't apply.

Don't understand the difference on the cache/VO Space option. I have always been uncomfortable with this anyway; I suggest we ALWAYS save to cache; when it appears the action already include "download", and VO Space is one of the places you can download to.

"Cache" means that the results are saved on the server. They last for a time that is discoverable, and sometimes negotiable, via UWS; it's fixed at 24 hours in DSA 2009.1.03. If results are sent to VOSpace then they last as long as the space allows, which is forever in a home space. These two arrangements are not really the same.

In the CEC interface, it's possible but impractical to save to cache. The implementation breaks for large results and will break anyway after a number of smaller results. -- GuyRixon - 2009-12-22

  • why is no "send to Topcat" etc option offered ? I seem to remember there is a technical reason for this but can't remember why.

  • the cached file is always called "result.txt", even if it supposed to be an html file. Then on my setup at least "view" opens it in a text viewer, not a a web browser. Shouldn't it be set to an appropriate extension depending on what is chosen in "Format" ?

  • The "Format" pull down is on the "Inputs" side, but really it should be "output" ?

All these issues are due to CEA. The ADQL query to the CEC interface is a real CEA request and the ADQL query to the TAP interface is handled as a fake CEA-request inside VODesktop. Taking the issues in reverse order:

  • The format parameter is implemented as a CEA input parameter, so appears in the inputs list.

  • The type of the output parameter representing the results is set in a fake CEA application-definition inside VODesktop, and it's set before the input parameter are read. Because the output format is variable, the correct type can't be set so it defaults to text.

  • The send-to-Topcat feature only works when an output parameter has a suitable type. Plain text doesn't activate this feature.

Really, we need a TAP UI that is not based on and constrained by CEA. -- GuyRixon - 2009-12-22 [Guy - on a timescale of six months we will have exactly this, with the VO Query joint project with CfA . It is looking very nice. Meanwhile, for this release we identify anything that is a quick-fix, and ignore more complicated problems... -- AndyLawrence 2009-12-22]

I"ve read the above section 3 times, and I'm still unclear what refers to what. If there's any points you want acting or commenting on, please rephrase below smile -- NoelWinstanley - 2010-01-04

Conclusion : We should ignore almost all of this for now : we will be doing it much better via the new VO Query. The key change has already been decided above : when TAP and CEA are both present, we only offer the "TAP Query" option, and leave the pane that results as it is for now. When there is a CEA that doesn't have a TAP, we can still offer the existing "Build ADQL" pane, but I suggest that the action offered in VO Explorer is called "ADQL (CEA) Query". Then at least we remove the ambiguity, and can improve the interface at a later date. -- AndyLawrence 2010-01-07

  • DONE renamed to 'ADQL Query' :the longer 'adql (cea) query' won't fit, and anyhow it fits in with the pattern of 'Table Query' for TAP services.


  • DONE Should we switch it off now ? Everything speaks SAMP ?
    • I've altered the default settings, so plastic hub is off by default. User can turn it on if required. -- NoelWinstanley - 2010-01-04

[Andy : Fine. Finished.]


  • I think this concept needs a slight update. If what I suggest here is easy, lets do it, but if its complicated we will leave it for a while.

  • "Recent Changes" isn't really an "example", and I find it quite interesting and useful. It could stand on its own, outside "Examples", at the top of the Resource Lists Pane. When you start on VO Explorer, it could by default load up that list. (At the moment the default is that nothing is selected and the Resource List pane is empty)

  • People really need to be eased into making their own folders and resource lists. Its a pain that you can't edit the Examples, because to understand how it works you really want. o I suggest we provide both a hardwired list and an ediatbel startup list. Then they can for example see how a query is made up, and try one of their own; and they can darg and drop additions to the static lists.

Both points above can be done - It's not technically hard, but the design choices are tricky. Some things to think about.
  • certain users (well, anita) didn't like a list loading on startup [Andy : I think its ok as long as its fast. At startup it doesn't load all the resource lists in the examples folder - it only loads each list when you click it, which seems fine.]
  • Recent changes can be expensive, especially if the UKIDSS resource (all 8 megs of it) has been updated in the last month / or vizier have republished everything - so maybe this isn't the best list to use at startup. [Andy : ok, agreed, but it doesn't load unless you select it, so I don't see the problem.]
  • The examples aren't editable for 2 reasons:
    • It was considered important that users couldn't inadvertantly trash their example lists. [Andy : agreed !]
    • The examples are a subscription - so we could add/update the examples in a timely fashion (pity it never really happened). Subscriptions aren't editable (as any changes would be overwritten next time the subscription was refreshed) [Andy : I am sure this is the right approach, and use of subscriptions by projects will grow] * Is it going to confuse users more if there's some example lists that are read-only, while others are editable? [Andy : see below]

Maybe if we keep the 'examples' as it, but then add a 'sandpit' folder containing some lists to muck about with? [Andy : yes ! thats what I meant.] Note that any example can be duplicated, and then edited at will. [Andy : yes of course, but we don't want that to be the first way users start experimenting. The sandpit idea is much better]. -- NoelWinstanley - 2010-01-04

Conclusions : Resource Lists pane starts with (i) "Recent Changes" implemented as a subscription, and not loaded at startup - only if user actually selects it. (ii) "Examples" folder implemented as a subscription, as now, but with updated contents. (iii) "Sandpit" folder implemented normally, so as to editable by user. Contents below. Can these have tooltips ? Then Examples would say "Example resource lists - not editable" whereas Sandpit would say "Editable examples". Recent changes would say "Fetch recent changes to AstroGrid Registry. Warning - may be slow". -- AndyLawrence - 2010-01-07

  • added tooltip to tree - although can't be edited in UI at moment, can be set programatically or by editing the subscription xml.
  • DONE done - now just waiting for changes to examples and sandbox lists.

Project Recommendations Examples

Put in here VO Taster list, Cone search examples, Image access examples, Spectrum Access examples, Queryable database examples, Remote applications, Solar services, VO EVent Services

I will update the contents these lists

Do you really want the title of this folder to be 'Project Recommendations'? - it seems a lot less clear than 'Examples' -- NoelWinstanley - 2010-01-04 [Andy : agreed]

Editable examples Sandpit

This can have IR redshift, SWIFT follow up, Radio images, Vizier AGN tables

Likewise I will have a look and update


*choice-cancel "apply" and "restore defaults" seem to be global

  • should it be possible to restore defaults just for the tab you are on ? Not sure whats best.
    • I intended apply and restore to apply just to the current tab - I've checked this, and that's the behaviour I'm seeing -- NoelWinstanley - 2010-01-04

[Andy : Understood and fine. Finished.]


  • DONE Can service table be the startup default ? I know I got outvoted once before, but I think this is actually the easiest version to use.
    • Astroscope remembers which view was last used, and re-opens in that view. I've set the service table to be the very first view shown to new users.

[Andy : jolly D. Finished.]

Issues found by Graham Relf

VO Desktop on XP

An error occurred while checking for new certificates Exception - Failed to create certificate directory - unable to install certificates * fixed this one by setting the working directory to something more sensible and restarting (edit/preferences)

I suspect that this feature could be disabled. The certificates in question are root certificates needed to enable MyProxy , which nobody is using in current VODesktop. The Accounts protocol, used to sign on at a community service, doesn't need root certificates. -- GuyRixon - 2009-12-22

DONE Removed certificate download code, and cached certificates - can still log in to leicester community fine. -- NoelWinstanley - 2010-01-04

An error occurred while starting internal plastic hub Could not read \\.Shared Folders\.plastic (The system cannot find the file specified) * don't know how to change location of .plastic file... but can uncheck "start PLASTIC hub at startup"

[Andy : I think we are all done here ? Nice email to Graham Relf would be good.]

  • yep - both of Grahams problems are sorted. I don't know his email address.

One More Thing : disappearing resource entries

While refreshing the examples list I noticed I had seen before but forgotten to highlight ... If a resource changes its IVOA ID, and you have it bookmarked in a static list, that entry simply becomes invisible. An example is ivo://wfau.roe.ac.uk/ssa-dsa which used to be ivo://wfau.roe.ac.uk/ssa-dsa/ssa. This was in the cone search examples list. I suddenly realised it wasn't there anymore. But when I edited the list, it was still there. But because the name is a resource that doesn't exist, VO Explorer simply doesn't display anything. Another example is the 2MASS image service ivo://irsa.ipac/2MASS-ASKYW-AT which changed its name to ivo://irsa.ipac/2MASS-ASKY-AT.

Would it not be better to display a standard "This resource does not exist" line, thus prompting user to investigate ?

  • Good point. In an ideal world, an IVOA ID would be forever, not just for christmas. In fact, it's kind of suggested by the specs that IVOA-IDs are eternal - and so resource publishers really shouldn't go changing them. Implementation-wise in the registry, the resources actually aren't removed - instead they're edited so that the attribute status='deleted'. However, an early design decision for voexplorer was that it wasn't going to show deleted or inactive resources (as they're no use to the user, and, as the vo matures, will outnumber the active resources - just causing clutter).
  • But because of this, you're right, static-lists will tend to degrade or decay over time. Smart lists don't have this problem. We should do something about it. Are you proposing displaying 'this resource does not exist' in the static list editor? or in the main resource table of voexplorer?

-- AndyLawrence - 2009-12-21

Topic revision: r12 - 2010-01-13 - 11:48:57 - NoelWinstanley
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