Cliff,

The function <tsrep> in the 'dates' library script converts timestamps
in 6!:0 format to integers (and vice versa). It seems like the integer
is the number of milliseconds between midnight on 1/1/1800 and the given
timestamp:

   load 'dates'
   ":!.13 tsrep 1800 1 1 0 0 0
0
   ":!.13 tsrep 1800 1 1 0 0 1
1000
   ":!.13 tsrep 1800 1 2 0 0 0
86400000

This may be what you're looking for; it shouldn't be hard to convert the
GPS timestamps to a suitable 6!:0 form.

/Chris

-----Original Message-----
From: Cliff Reiter [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, May 23, 2007 3:56 PM
To: General forum
Subject: [Jgeneral] Date/Time to numeric utilities

Hello forum,
I have data coming from GPS Track points where, for example, the first
and last track point entries in a 33km snowshoeing trek in April are of
the form

    ({.,{:) tp_in_lap_x >45{laps
+--------------------+--------------------------------+
|2007-04-21T10:15:08Z|44.1936 _73.9555 646.624 5.10308|
+--------------------+--------------------------------+
|2007-04-22T00:06:59Z|44.1934 _73.9554 634.607 33385.9|
+--------------------+--------------------------------+

I would like to use the time info numerically and can do what I need by
ripping the time/date string apart and creating time in seconds; but
when the date changes during the trek come into play, as above, the
details become complex (leap days, etc).

Are there standard J utilities for converting Date/time text into a
standard numeric form that accounts for the complexities of dates?

Best,
Cliff

--
Clifford A. Reiter
Mathematics Department, Lafayette College
Easton, PA 18042 USA,   610-330-5277
http://www.lafayette.edu/~reiterc

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