Known time desc » History » Revision 29
Revision 28 (Anonymous, 08/07/2016 11:42 AM) → Revision 29/31 (Anonymous, 08/07/2016 12:15 PM)
h1. Known time description h2. Double Time ranges : date from 01/01/1970 to 01/01/2100 * seconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000 * milliseconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000 000 (ambiguity for the first 48days of 1970 with previous time format) * seconds from 01/01/0000 00:00:00 : 62 168 472 000 to 66 270 960 000 (no ambiguity) * milliseconds from 01/01/0000 00:00:00 : 62 168 472 000 000 to 66 270 960 000 000 (no ambiguity) * seconds from 01/01/2000 00:00:00 : - 946 728 000 to 3 155 760 000 (TT2000) * milliseconds from 01/01/2000 00:00:00 : - 946 728 000 000 to 3 155 760 000 000 (ambiguity with TT2000 in seconds?) µs, ns, ps might also be needed for tt2000 Double (IEEE754) 64bits min value: -1.7977E+308 max value :1.7977E+308 h2. Known time description |_.Mission Name |_.time var name |_. units |_.DEPEND |_.LABLAXIS|_.FIELDNAM |_.CATDESC |_.Type |_.VIRTUAL|_.nb of records|_.VAR_NOTES| |Cluster FGM |time_tags__CDFNAME |ms |0 |UT |Universal Time |Interval centred time tag |CDF_EPOCH | |normal |field missing| |Cluster HIA |time_tags__CDFNAME |ms |0 |UT |Center Time |Interval centred time tag |CDF_EPOCH | |normal |field missing| |||||||||||| |Themis Efi,SCM |VARNAME_time |sec |TIME |UT |Same as time var name|UTC, in seconds sinc 01-Jan-1970 00:00:00|CDF_DOUBLE | |normal |Unleaped seconds| |Themis Efi,SCM |VARNAME_epoch |field missing|0 |UT |Same as time var name|Unrelated |CDF_EPOCH |true |0 |field missing| |Themis Efi,SCM |VARNAME_dot0_epoch0|msec |EPOCH0 |UT |Same as time var name|EPOCH of THEMIS time base |CDF_EPOCH | |1 |EPOCH of 01-Jan-1970 00:00:00| |Themis Esa |VARNAME_time |sec |TIME |UT |Same as time var name|UTC, in seconds sinc 01-Jan-1970 00:00:00|CDF_REAL8 | |normal |Unleaped seconds| |Themis Esa |VARNAME_epoch |field missing|0 |UT |Same as time var name|Unrelated |CDF_EPOCH |true |0 |field missing| |Themis Esa |VARNAME_dot0_epoch0|msec |EPOCH0 |UT |Same as time var name|EPOCH of THEMIS time base |CDF_EPOCH | |1 |EPOCH of 01-Jan-1970 00:00:00| |Themis Peer |VARNAME_time |sec |TIME |UT |Same as time var name|UTC, in seconds sinc 01-Jan-1970 00:00:00|CDF_DOUBLE | |> data |Unleaped seconds| |Themis Peer |VARNAME_epoch |field missing |0 |UT |Same as time var name|VARNAME |CDF_EPOCH | |normal |field missing| |Themis Peer |VARNAME_epoch0 |msec |EPOCH0 |timebase |Same as time var name|EPOCH of THEMIS time base |CDF_EPOCH | |1 |EPOCH of 01-Jan-1970 00:00:00| |||||||||||| |MMS fpi |Epoch (absent, Epoch_minus_var is present) |s |0 |Field missing | VARNAME|VARNAME |CDF_UINT1 | |1 |VARNAME| |MMS scm |epoch_timetag |ns |0 |VARNAME |Same as time var name|Packet time time |CDF_TIME_TT2000| |normal |field missing| |MMS scm |Epoch (other var time) |ns |0 |VARNAME |Same as time var name|Time |CDF_TIME_TT2000| |normal |field missing| |||||||||||| |ACE mfi |Epoch |ms |0 |VARNAME |Time |Time ,beginning of interval |CDF_EPOCH | |normal |field missing| |||||||||||| |Helios nessmag |Epoch |ms |0 |field missing |Epoch |Default Time |CDF_EPOCH | |normal |field missing| |||||||||||| |Ulysses hft |Epoch |ms |0 |Time |Epoch |Time in NSSDC Epoch format |CDF_EPOCH | |normal |field missing| |||||||||||| |SOHO cst |Epoch |ms |0 |Epoch |Time Line |Time |CDF_EPOCH | |normal |field missing| h2. Algorithm Proposition VariableThatNeedsTime depend0 = get(VariableThatNeedsTime.DEPEND_0 variable) if(depend0.nbOfRec == VariableThatNeedsTime.nbOfRec) * test depend0.firstValue for different double range mentionned above (this part might include CDF_TYPE for TT2000) * if(ambiguity) ** look at depend0.units ** if field is missing, look at VariableThatNeedsTime.depend_epoch0.units field //ATM, these lines are written, epoch0 units are useless since that variable only appears when matching time is DEPEND_TIME variable else dependTime = get(VariableThatNeedsTime.DEPEND_TIME variable) if(dependTime.nbOfRec == VariableThatNeedsTime.nbOfRec) * test dependTime.firstValue for different double range mentionned above (this part might include CDF_TYPE for TT2000) * if(ambiguity) ** look at dependTime.units h2. Useful links http://spdf.gsfc.nasa.gov/CDFconversion/time_formats.html http://cdf.gsfc.nasa.gov/html/leapseconds_requirements.html how autoplot is processing cdf files : http://autoplot.org/help#Reading_CDF