plot_mass_vs_semimajoraxis_eccentricity.python

#!/usr/bin/python
import xml.etree.ElementTree as ET
import subprocess, glob, os, datetime

# Open pipe gnuplot. You may want to change the terminal from svg to pdf for publication quality plots.
gnuplot = subprocess.Popen(['gnuplot',"-persist"], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
gnuplot.stdin.write("""
set terminal svg
set output "plot_mass_vs_semimajoraxis_eccentricity.svg"
set xlabel "Semi-major axis [AU]"
set ylabel "Planet mass [MJupiter]"
set cblabel "Eccentricity"
set logscale xy
set xrange [0.001:80]
set yrange [0.008:25]
set label "Data taken from the Open Exoplanet Catalogue. Last updated on {0}." at screen 0.19,0.15 front font ",8"
plot "-" with point pt 7 lc palette notit
""".format(datetime.date.today().isoformat()).encode('utf-8'))
for filename in glob.glob("open_exoplanet_catalogue/systems/*.xml"):
	system = ET.parse(open(filename, 'r'))
	planets = system.findall(".//planet")
	for planet in planets:
		try:
			mass = float(planet.findtext("./mass"))
			semimajoraxis = float(planet.findtext("./semimajoraxis"))
			try:
				eccentricity = float(planet.findtext("./eccentricity"))
			except:
				eccentricity = 0.
			gnuplot.stdin.write("{0:e}\t{1:e}\t{2:e}\n".format(
				mass, semimajoraxis,
				eccentricity).encode('utf-8'))
		except:
			# Mass or semimajoraxis not specified for this planet.
			# One could do a more complicated check here and see if the period and the mass of the host star is given. 
			pass


gnuplot.stdin.write("\ne\n".encode('utf-8'))

gnuplot.stdin.close()