Notable Improvements:

1. No more "out of memory" errors when performing large queries:

  • An extensive rewrite of the astroserver application allows unlimited output size as data is now written directly to disk and not fully buffered in memory
  • The size of FITS output files can be limited (by both data-table size in number of rows or total bytes) with command-line options. When an output file reaches this limit it is split into multiple files. If a file requires splitting an '@-file', containing the list of output files, is also generated so users can pass this file using the '@' prefix to ftools and science tools which support taking a list of input files
  • FITS output (FT1, LS1, and FT2 30s/1s) files are limited, by default, to 4.0GB to avoid potential problems with Science Tools which use the TIP libray which may have trouble with FITS tables larger than 4GB.
    • The relevent options can be used (with a value of '0' (zero)) to disable output-splitting. This is not yet available in the web interface; an 'expert'-option or GUI element will be added in the near future

2. Command-line help:

  • A new command-line option ("-h" or "--help") will display a help page on standard out, listing program usage and a description of all available options
  • Another new option ("-i" or "--info") will display a list of available Event Samples. The Event Samples are required in event or ft2 queries and are specified using the "--event-sample" option. This option also shows other basic information for each Event Sample such as the range of event-classes and available output formats
  • The 'bounds' command (requires an event-sample to be specified) will give specific information about an Event Sample such as the MET time spanned.

CHECKSUM and DATASUM Note:

  • The Java FITS library is only capable of calculating CHECKSUM and DATASUM keywords if all data is buffered in memory. These header cards are now written with blank values by the astro-server application. A shell-script is written alongside each output file which can be invoked to fix the CHECKSUM and DATASUM keywords of your FITS file if you wish. You will need to have the FTools in your path so fchecksum is available. The web interface automatically invokes these scripts after successful completion, the command-line does not.

Backward-Compatibility Notes:

1. '--eventClass' option deprecated. Replaced by '--event-class' option. New option takes a comma-separated list of event classes, or ranges thereof. Ranges are separated by colons. Open-ended ranges are denoted by a single event class preceded or followed by a colon character. For example:

  • 1,3 == 1 or 3
  • 1:3 == 1,...,3 (range)
  • :3 == <=3 (left-sided range)
  • 3: == >=3 (right-sided range)
  • 1,3,5: == 1,3,>=5 (etc...)

Where to Get Access:

On the web

A new web interface is installed at the following address:

http://glast-ground.slac.stanford.edu/DataPortalAstroServer/skimmer.jsp

Command Line (SLAC Unix systems)

The new command-line interface is available here:

         /afs/slac.stanford.edu/u/gl/glast/astroserver/prod/astro

Try executing the following command to see the help screen:

         /afs/slac.stanford.edu/u/gl/glast/astroserver/prod/astro -h

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1 Comment

  1. Daniel Flath

    Sample Command line, or two... 

    Here's how you'd get all class 2 & 3 photons in a 15 degree radius about RA=0,DEC=0 in a small time range:

         ~glast/astroserver/prod/astro store --event-sample P6_public_v1 --minTimestamp 2.5E8 --maxTimestamp 2.51E8 --ra 0 --dec 0 --radius 15 --event-class 2,3 --output-ft1 test-ft1.fits

    Here's how you'd get all the 1-second FT2 data into a single output file (by disabling file splitting):

         ~glast/astroserver/prod/astro storeft2 --event-sample P6_public_v1 --output-ft2-1s all-ft2-1s.fits --output-ft2-1s-max-bytes-per-file 0

    The 'bounds' command shows you the valid ranges of the major parameters like time, and energy:

         ~glast/astroserver/prod/astro bounds --event-sample P6_public_v1

    Available Event Samples can be listed with the following command:

         ~glast/astroserver/prod/astro --info

    Although, at the time of this writing, the average user should be using the "P6_public_v1" sample.