[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[no subject]

Robert,

The nldn files on the IDD transmit a field for "nanoseconds", which
is used to create the milliseconds field that DCNLDN is storing.
Looking at the data that is being transmitted, the nanoseconds value
is always appearing as an even tenth of a second multiple, eg:

sec 961704003 nsec 300000000

Thus, converting the nsec value to 300 milliseconds is not losing any
presicion in the decoding at your end. Rather, it is already being
coded as a number with 1/10s resolution when the data file is
created by the provider.

We will see if the providers of our NLDN data stream can give us more
information on how the data is being processed to create the IDD
datastream products and if the data values are being truncated.

Steve Chiswell
Unidata User Support






>From: Robert Holzworth <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200006221835.e5MIZXT27254

>Re: NLDN time resolution in data to UW
>Dear Unidata,
>I am a professor at the Univ. of Washington and Harry Edmon
>(Atmospheric Sciences Department) suggested you may be able 
>to answer my question.  
>We get NLDN from you on a regular basis, but it seems to have time
>resolution only to the 1/10 of a second level (0.1s), right?
>
>How can we get millisecond resolution?  The data files you
>send have the time with space for the digits to the
>millisecond, but the 10ms and 1ms digits are always zero:
>time: 23.100  instead of 23.132 for an event at 132 ms after
>the 23rd second.
>
>I realize this will make our data set expand somewhat because
>multiplicity will then always be 1, I guess.  However, for
>experiments I am doing this month and next we will need
>stroke-level NLDN data.  
>
>Is it possible to increase the time resolution for us?  If
>this is a problem for the routine processing, would it be
>possible to get stroke level data after the fact for
>particular subsets of the data?  
>
>Thanks,
>Bob Holzworth
>************************************************
>Prof. Robert H. Holzworth
>Graduate Program Advisor in Geophysics
>University of Washington
>Room 202 ATG Building
>GEOPHYSICS 
>Box 351650                   
>Seattle, WA 98195-1650, USA 
>************************************************
>address@hidden 
>http://www.geophys.washington.edu/People/Faculty/bobholz/
>************************************************
>206 685 7410 (office & voice mail)
>206 685 3815 (fax)
>************************************************
>