An example would certainly be in order. Within Ingrid/IRI data library, the url for a dataset is a virtual directory, different files within that directory contain the different representations of that dataset, e.g. dods.das, dods.dds, dods.dods, data.cdf, data.r4, data.s4, data.txt, index.html, index.xml, .... . Filters on the data and metadata appear as subdirectories, e.g. a filter which transforms the metadata to be COARDS compliant would mean appending COARDS/ to the dataseturl. There are also filters for averaging, svd analysis, etc, but I was not trying to go there at the moment.
To describe this as a serviceList, I would envision something like the following:
<servicelist ID="Ingrid" base="http://iridl.ldeo.columbia.edu/">
<service type="DODS" urlsuffix="dods">
<service type="DODS" subtype="COARDS" urlsuffix="COARDS/dods">
<service type="netcdf" urlsuffix="data.cdf">
<service type="netcdf" subtype="COARDS" urlsuffix="COARDS/data.cdf">
</servicelist>
...
<collection name="LEVITUS94">
<collection name="ANNUAL">
<dataset name="PO4" serverID="Ingrid" dataType="GRID" urlPath="SOURCES/.LEVITUS94/.ANNUAL/.PO4/"/>
<dataset
name="NO3" serverID="Ingrid" dataType="GRID" urlPath="SOURCES/.LEVITUS94/.ANNUAL/.NO3/"/>
<dataset
name="temp" serverID="Ingrid" dataType="GRID" urlPath="SOURCES/.LEVITUS94/.ANNUAL/.temp/"/>
...
</collection>
...
</collection>
.....
And I would hope the client would generate DODS base urls like
http://iridl.ldeo.columbia.edu/SOURCES/.LEVITUS94/.ANNUAL/.PO4/dods
or
http://iridl.ldeo.columbia.edu/SOURCES/.LEVITUS94/.ANNUAL/.PO4/COARDS/dods
depending on whether it wanted the COARDS subtype or not.
One could envision large service lists, so one might want to allow doing it by reference (would only have to download a servers servicelist once).
Benno
P.S. the 'netcdf' service above refers to http delivery of complete netcdf files: I only include it as an example and probably would not advertise the service since I would rather clients use DODS anyway.
--------------------------------------------------------------------
John Caron wrote:
----- Original Message -----
From: "Benno Blumenthal" <address@hidden>
To: "John Caron" <address@hidden>
Cc: <address@hidden>
Sent: Tuesday, May 14, 2002 12:36 PM
Subject: Re: New Catalog XML Draft> It would be particularly nice if we could specify suffixes in the service
list
> as well, for servers that add different suffixes for different datatypes.
>
> I was also wondering about service subtypes, e.g. COOARDS for netcdf
files,
> since many client developers insist on COOADS, it would be nice for
servers that
> are more general to be able to also generate DODS datasets with (and
without)
> COOADS metadata.could you give me an example for both these ideas of how this would look in
XML and how it would be handled at the client or server?
-- Dr. M. Benno Blumenthal address@hidden International Research Institute for climate prediction Lamont-Doherty Earth Observatory of Columbia University Palisades NY 10964-8000 (845) 680-4450