Hello all,
I've taken VOFilter for a test drive; you'll find my comments on it below
Cheers,
Bruno
**Preparing**
VOFilter 2.0 requires OpenOffice 2.0, which is currently in beta stage,
called as version 1.9.122.
Notice that trying to load VOFilter on a previous version of OpenOffice
results in an "installed successfuly" message, but when trying to open
a VOTable file, it simply opens a blank spreadsheet.
And although it's missing from the requirements, VOFilter 2.0 requires a JVM.
**Benchmarking**
A point of interest was to see how would VOFilter 2.0 would perform when compared to VoFilter 1.0. The short story: VOFilter 2.0 is faster than VOFilter 1.0, by a huge amount.
The long story:
My setup:
Pentium M 1.4GHz, 1GB RAM
Windows XP SP2
Java 1.4.2_05
OpenOffice 1.9.122
The first file takes longer to load (around 5 sec for a small file). Certainly OpenOffice is loading the JVM and/or VOFilter into memory. So the following numbers are for files loaded after that.
I used VOTable files generated by ESO archive and Vizier containing
search results. Load times were roughly 2000 rows/sec for ESO's
archive, and 900 rows/sec for Vizier.
The Vizier files are larger: they contained more columns.
To be able to load very large files (what large files are depends on
their origin; for ESO archive it was above 15000 rows, or 2MB), I had
to change the default memory settings for the JVM to use up to 256 MB
of RAM (-Xmx256m), since it raised an error: "General Error. General
input/output error."
Suggestion: add this tip to the web page under the Limitations section.
**General appraisal**
The VOTable metadata is loaded as a separate spreadsheet, so it is easily accessible, just like the data. Suggestion: create a note (tooltip) for the "header" cells on the data spreadsheet, containg a small description (the units would be useful) for quick access.
VOFilter 2.0 lost that hability to write the data in VOTable format (1.0 could). I don't see any big use for it anyway; but it would be desirable to be aware of it by reading the top of the webpage.
Suggestions for improvement: Take advantage of the LINK element on the
VOTable matadata for a given FIELD element, and create links on the
corresponding data cells:
http://www.ivoa.net/Documents/REC/VOTable/VOTable-20040811.html#ToC46
VOTable data is loaded as text in the OO spreadsheet; this might be
a good thing, since it doesn't make dangerous assumptions on the data,
but it takes a bit too much effort to get value from the data. While
drawing a plot from the VOTable data, I had to use OpenOffice formulas
in order to get to the data:
- ESO archive: RA and Dec are in hexagesimal format