title: Convert Julian Date to PosixCt Date
body: <p>I find myself struggling with this problem: I need to convert a julian date to normal date (&quot;YYYY-MM-DD&quot;) in R. I'm aware that I can specify <code>as.Date(julian_date,origin=&quot;&quot;)</code>, but I don't know which origin should be provided.</p>
  <p>My julian dates are something like 2458010,2458011 etc..
  If I stay with default origin (&quot;1970-01-01&quot;) my dates becomes something like &quot;8699-11-10&quot; which is obviously wrong since I know dates should be in years 2017-2018</p>
  <p>How do I know the correct origin for the <code>as.Date</code> function? <a href="http://www.onlineconversion.com/julian_date.htm" rel="nofollow noreferrer">http://www.onlineconversion.com/julian_date.htm</a> This site seems to convert my julian dates in the right way...</p>