Changes between Initial Version and Version 1 of VsoFAQ2

Timestamp:

06/10/05 13:05:20 (19 years ago)

Author:

joe

Comment:

--

VsoFAQ2

@@ +1 @@
+= Infrequently Asked Questions =
+
+== (and known bugs/problems) ==
+
+You may also want to take a look at the [wiki:VsoFAQ Frequently Asked Questions] list.
+
+
+== Questions ==
+
+
+=== How do I file a problem report or suggestion for improvement? ===
+
+
+
+We suggest you use
+our general feedback form 
+'''[http://virtualsolar.org/feedback/ http://virtualsolar.org/feedback/]''',
+or email your reports/comments/suggestions to:
+''VSO-AT-spd.aas.org''.  You can also fill out our
+'''[http://vso.stanford.edu/vso_feedback.html user survey]''' so we can
+prioritize based on the needs of the user community.
+
+You should also check that you are using the most recent version
+of VSO.  The most recent link will always be available from the VSO homepage
+at '''http://virtualsolar.org/'''.
+
+=== I have a digital data archive and I would like to make the data available through VSO.  What do I have to do? ===
+
+Please contact one of the VSO scientists (Rick Bogart, Joe Gurman, Frank Hill,
+Piet Martens) and let us know of your interest.  Extension of data service
+providers is the highest priority for VSO.  We have an adoptor's kit, and
+assistance available to help tie your archive into VSO.
+
+The majority of the work from the provider is in attempting to describe
+your holdings in terms of the VSO Data Model, so that the VSO has
+accurate information about the type of information that your organization
+providers.
+
+=== Are there limits to the number of query results returned?  If so, what are they? ===
+
+Yes.  Each data provider may have limits to prevent their systems
+from returning exceptionally large results.  Because of the way in which
+VSO breaks queries down into simpler queries for the individual data
+providers to process, it is difficult to say just how many records an
+individual data provider will return.
+
+=== How do I know if the number of query results was truncated by the data server? ===
+
+The results page lists two numbers -- the number of records returned, and the
+number of records found.  If the two are not equal, it means that one the
+data providers has reached its internal limit, and not returned all of its
+records that matched the query.  If the number of records found is not displayed,
+it suggests that the data provider had reached its limit, but did not determine
+how many additional records there were.  [This should only occur if the cost in
+performing an exhaustive search would be prohibitive].
+
+We are trying to find a good balance between obtaining the desired results,
+while preventing there from being an undue burden on individual data archives,
+and the mechanisms for handling this scenario may be changed in the future.
+
+=== When I request data, do they have to go through the VSO?  How long does it take to get the data? ===
+
+No data go through VSO.  VSO only handles the process of locating, and ordering
+the data.  The actual data delivery is handled by the user and the individual
+data providers, although it is possible that some user interfaces may add
+additional value by automatically following URLs to download information.
+For more information about the transfer of data, see the
+'''[http://vso1.nascom.nasa.gov/API/VSO_API.html#negotiation API documentation on Transfer Negotiation]'''.  Additional information is available
+for the '''[http://vso.nascom.nasa.gov/cgi-bin/show_details.pl?keyword=PROVIDER data providers]''', but
+is currently in the process of being updated.
+
+=== When I submit a query, at the end of the list of results it says Session ID: followed by a long incomprehensible hexadecimal string.  What does it mean? === 
+
+You may be using an older version of VSO.  Please make sure you are
+connecting to the most recent
+'''[http://vso.nascom.nasa.gov/cgi-bin/search VSO Search Interface]'''.  We are experimenting with mechanisms for recording
+search parameters and/or results (at the option of the user), so that
+any particular
+useful query can automatically be regenerated if desired, or referred to
+in publication of results.
+
+
+
+=== All queries seem to go through and require the (''some organization'') VSO site.  What is virtual about the Virtual Solar Observatory? ===
+
+There originally was a single prototype implementation at Stanford.  That has
+since been replaced with a system that is distributed across Stanford, NASA,
+and NSO, not including the functionality at each of the individual data
+providers.
+
+What is virtual about VSO is that there is no one master archive or
+database of all of the holdings.  There is a point of entry that users
+or applications can interact with, to access data that is spread across multiple
+systems.  This concept is commonly refered to as 'Data Virtualization'.  Additionally,
+there is virtualization on another scale, as there is no one single server --
+Although there is a reference system, at
+'''http://virtualsolar.org/''', its 
+purpose is to provide a unified starting point to people new to the VSO,
+and is not involved with the actual processing of the VSO, which currently 
+has multiplexors at SDAC, Stanford, and NSO.
+
+=== The information in the server data registries does not always match what is actually searchable.  Are the displayed data registries different from those used by the user interface? ===
+
+Please '''[wiki:ContactUs send us details]'''
+about what you have found that doesn't seem to be in agreement, or 
+what query you used, that you had expected data to be returned for.
+
+=== What do all the funny colors on the results pages mean? ===
+
+For ease of navigating among large numbers of return results, every
+fifth entry from each data provider is highlighted in yellow, every
+tenth in green, and every hundredth in blue.  No special significance
+attaches to these entries.
+
+
+== Problems ==
+
+=== When I query data from the (Montana State University|Mauna Loa) archive, I get lists in which apparently identical data sets are reproduced from two to seven times.  When I download these data sets, they are indeed identical. ===
+
+Observations in the MSU Yohkoh SXT archive are catalogued individually but packaged
+together in orbit files.  If several observations in the same file match
+the search criterion they will each return a record, but the records will
+all point to the same distribution file.  Downloading any one will of course
+get you all the data in the orbit file.
+
+Observations in the MLSO archive are stored in both JPEG and FITS formats.
+Although the observations occur in the listings twice, they point to
+different data products.  It is possible that this may change in the future,
+depending on user feedback. #13
+
+=== I don't see any data from the McMath FTS Spectrometer, though it shows up in the NSO list of instruments. ===
+
+The VSO has helped us to shed light on the fact that some metadata
+are not correct.  In this particular case, most of the datasets listed
+from the Kitt Peak 512-Channel Magnetograph
+and from the Evans Spectroheliograph have end times earlier than the start
+times.  Occasionally there are multiple entries that are apparently identical
+(e.g. KPVT Magnetograph 1993.04.10).
+
+=== I don't see any data for the last day of my time range request from the GOLF instrument, even though I know it is there; it shows up if I extend the range of time by even one minute. ===
+
+Please make sure you are using the most recent version of VSO.  Early versions
+of VSO required the observation to be completely contained within the search
+range.  The current implementation performs range matching by searching for 
+non-vanishing intersection.
+
+
+=== When I query the Stanford Heleioseismology Archive for ground-based data I sometimes see records whose start and end times are both outside my requested time interval. ===
+
+Range matches (in this case, time range), is done by finding a non-vanishing
+intersection.  If you would prefer a different type of range matching, please
+'''[wiki:ContactUs let us know]''', so we can
+prioritize new functionality.
+
+The Stanford datasets are generally for sets of images spanning a long
+time interval, typically a day for ground-based instruments.  Although
+the datasets have registered start and end times corresponding to the
+first and last images of the day, they are in fact searched by an index
+number corresponding to the day number, starting at local midnight.
+In order to assure that no relevant records are missed from sites whose
+observations can span two UT days, the Stanford server returns matches
+for both day numbers.