Accessing GSA Data from Scripts

Gemini files can be retrieved directly from your scripts by using a URL's of the form "http://www.cadc.hia.nrc.gc.ca/getData?" for public data or "http://www.cadc.hia.nrc.gc.ca/getData/auth?" for proprietary datasets (with the appropriate authorization passed as parameters - see below). Note that Gemini files are stored in gzipped format so either form of the getData URL will return a compressed file.

For example, below is a trivial PERL script that retrieves three public files from the GSA:

  #!/usr/bin/env perl 
  use strict;

  my @files    = ( "S20070408S0107", "S20070408S0106", "S20070407S0066" );
  my $baseUrl  = "http://www.cadc.hia.nrc.gc.ca/getData";
  my ( $fileId );

  foreach $fileId (@files)
  {
    `curl -g -o $fileId.fits.gz "$baseUrl?archive=GEMINI\&file_id=$fileId"`;
  }

  exit();

You can also retrieve proprietary files (if you have authorization!) by modifying this basic script as shown below. Note the "auth" appended to $baseURL as well as the use of your CADC user account information.

  #!/usr/bin/env perl 
  use strict;

  my $baseUrl       = "http://www.cadc.hia.nrc.gc.ca/getData/auth";
  my $cadcUserId    = "dbohlender";  # Your CADC user ID
  my $passWord      = "????????";    # Your CADC account password
  my @files         = ( "N20081011S0191", "N20081011S0190", "N20081010S0545" );
  my ( $fileId );

  foreach $fileId (@files)
  {
    `curl -g -o $fileId.fits.gz -u $cadcUserId:$passWord 
        "$baseUrl?archive=GEMINI\&file_id=$fileId\&user=$cadcUserId\&password=$passWord"`;
  }

  exit();
  

You can find more details and other examples of "getData" usage, including retrieval of FITS header content, here.