GaiaTest.frink

View or download GaiaTest.frink in plain text format


/* This program demonstrates graphing star positions with the Gaia satellite
   data, specifically the data release 2 data.

   It requires downloading the Gaia data (which is huge if you download it
   all; the whole database is about 550 GB, and those are mostly gzipped
   files!) from:
   http://cdn.gea.esac.esa.int/Gaia/gdr2/

   This program just uses the limited data set in gaia_source_with_rv which
   contains data for about 7.2 million stars.  The full data set contains about
   1.2 billion stars.

   The data for gaia_source_with_rv can be downloaded directly from
   http://cdn.gea.esac.esa.int/Gaia/gdr2/gaia_source_with_rv/csv/

   which is about 3.1 GB (gzipped!) of data; it's about 7.5 GB uncompressed.
   The new gunzip function in Frink will allow you to process gzip-compressed
   files in place.

   Description of the whole data release is available at:
   http://gea.esac.esa.int/archive/documentation/GDR2/

   More specifically, the description of the gaia_source table used in this
   program is available in section 14.1.1 of that document at:
   http://gea.esac.esa.int/archive/documentation/GDR2/Gaia_archive/chap_datamodel/sec_dm_main_tables/ssec_dm_gaia_source.html

*/



// Modify this path to where your Gaia files reside
dir = "/home/eliasen/builds/Gaia/gdr2/gaia_source_with_rv/csv"

g = new graphics
g.backgroundColor[0,0,0]
g.color[1,1,1,.5]

for url = select[fileURLs[dir], %r/\.csv\.gz/]
{
   println[url]
   lineNum = 0
   for line = lines[gunzip[url]]
   {
      if lineNum != 0
      {
         fields = split[%r/,/, line]
         ra = eval[fields@5] degrees
         decl = eval[fields@7] degrees
         g.fillRectCenter[ra, decl, .1 degree, .1 degree]
      }
      lineNum = lineNum + 1
   }
}

println["Done reading.  About to render graphics to screen."]
g.show[]
println["Done showing."]

println["Inverting grays."]
g2 = g.invertGrays[]
println["Done inverting grays.  Beginning printing"]
g2.print[]
println["Done printing."]


View or download GaiaTest.frink in plain text format


This is a program written in the programming language Frink.
For more information, view the Frink Documentation or see More Sample Frink Programs.

Alan Eliasen was born 17865 days, 22 hours, 27 minutes ago.