Hi I think there is a bug in the conversion routines jul2num() and num2jul(). I tried to define a date axis for satellite data. The time is measured in a modified Julian Date (JD). So reading in the data and then doing
mp = julian2num(jd) dates = num2date(mp) resulted in an error "year out of range" (or so). I looked at the values and they were way to high. Inspection of the source date.py showed for the conversion routines julian2num: j + 1721425.5 num2julian: j - 1721425.5 Since the JD measures days from 4713 BC - earlier than the matplotlib zeropoint - the conversion should be the other way round, i.e. for julian2num we should subtract. After correcting this, I could still not reconcile my measurement dates with the result of num2date(). In the source it is stated that counting starts at 0001-01-01 00:00:00 UTC (JD 1721423.5), which BTW does not match the number used in the routines. The only way to correct this was to use an offset of JD 1721424.5 (January 2nd, 0001, 00:00:00). So the correct formulae should be julian2num: j - 1721424.5 num2julian: j + 1721424.5 or am I missing something? VERSION INFO: matplotlib V. 0.99.1.1/python 2.6.2 on opensuse 11.2/x86_64 Cheers gl -- Günter Lichtenberg ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
