Spectral cutout service

[Douglas Tody]

On Fri, 3 Oct 2008, Petr Skoda wrote:

>> While this is the intention, I am yet not aware of any SSAP services that 
>> can do cutouts.
>
> We have found some way how to do it using the Pleinpot (due to my 
> collaboration with Philippe Prugniel) - but he wants to have exact definition 
> of such a service before modifying Pleinpot.

Since SSA spectra may be computed on the fly it should be clear how
to do a cutout.  You just describe the cutout spectrum, and later
compute it if it is actually accessed.

> The most interesting question from him is:
>
> How we know that the service is a cutout service ? We do not yet have 
> GetCapability implemented (and approved in RFC) so the only way I see (and 
> what was confirmed by Bob Hanisch) is simply another ServiceURL (another name 
> of *.cgi in our case)..
> Or is there another solution how to do it now in current standards ?
> Phillipe's objection is the mess in delivering the results - the user has to 
> control what he really wants to do with the data - see them all or get the 
> selected range -- I think that it is clear - I would simply call another 
> service which will be in Registry named as "archiv xxx cutout service  " with 
> different ServiceURL. But what it should give in FORMAT=METADATA ?

Services which do cutouts and services which return archival spectra
would normally be separate services, separately registered (hence a
different service URL as you say).

We need to describe the service type both in the registry, and in
getCapabilities.  Just getting it into the registry somehow would
be enough for now, until we update SSA to V1.1 with getCapabilities
(at this point we are waiting for a first round of experience with
the initial implementations before doing the update).

So the real question is how to distinguish a cutout-type SSA service
in the registry?  Note we already have a registry Capability schema
for SSA 1.0.  Offhand I don't recall the details, but this would
be the place to put this information, and we would not have to wait
for getCapabilities.  Normally one wants to find cutout services via
the registry before going to the service in any case.

This would be a good thing to look into by the time of the interop.

>> other capabilities, e.g., for association to describe complex data
>> aggregations.
> It is exactly what I would like to do in the future - delivering the 
> individual echelle orders (somehow preprocessed...) - some clever way of 
> presenting IRAF *.ec files .....

You should be able do this via association now, in the query response.

 	- Doug