# ISO-8601 3.25 Second, Leap Applications requiring leap seconds

HJWOUDENBERG at aol.com HJWOUDENBERG at aol.com
Tue Jan 4 00:52:05 UTC 2005

```Applications
*   astrometry
*   geophysics
*   orbitography
*   positionning
IREP
_http://hpiers.obspm.fr/eop-pc/_ (http://hpiers.obspm.fr/eop-pc/)

Has anyone used them in a commercial  application?

I think I have an efficent method to include leap seconds however, but  don't
plan to program it until I know there is a need..

Anyone have ideas on how to notfiy the software to include or exclude leap
seconds?

Solution for including leaps seconds:
Convert the year to binary value.
If the months are the first  quarter of the year
mutiply  by 4.
If the months  are the second quarter of the year
Multiply  by 4 and add 1.
If the third quarter
Multiply  by 4 and add 2
If the fourth quarter
Multiply  by 4 and add 3
Us the binary result as an index into a table.
Each postion of the table contains the cumulative  binary leap seconds.
Add the cumulative leap seconds to the seconds in  the date.
For every year the table will have four entrys per  year. for 03-31, 06:30,
09-30 12-31

One bytes allows 256 cumulative seconds.

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