Download or view 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
[colToName, nameToCol] = makeColumnDictionaries[line]
else
{
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."]
/** Makes two dictionaries that map column numbers to column
names and vice versa.
Returns:
[colToName, nameToCol]
*/
makeColumnDictionaries[line, print=false] :=
{
fields = split[%r/,/, line]
colToName = new dict
for i = rangeOf[fields]
colToName@i = fields@i
nameToCol = colToName.invert[]
if print
{
for key = sort[keys[colToName]]
println["$key\t" + colToName@key]
println[]
println[]
for key = lexicalSort[keys[nameToCol]]
println[nameToCol@key + "\t$key"]
}
return[colToName, nameToCol]
}
Download or view 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, eliasen@mindspring.com