20050630: McIDAS: Time selection for PTDISP

>From: "Kwan-yin Kong" <address@hidden>
>Organization: CCNY
>Keywords: 200506301931.j5UJVhjo014239 McIDAS PTDISP MD TIME HMS

Hi Kwan,

>      Hi.  This is Kwan-yin Kong at CCNY.  We haven't 
>contacted for quite a while.  How has everything been 
>going?

Good, thank you.  I hope that you have been well also.

>Currently, I am trying to selectively display 
>surface observations in a certain range of minutes within 
>the hour.  The command I entered was:
>
>PTDISP RTPTSRC/SFCHOURLY 1 PAR=T[F] TD[F] PSL[MB] GUS[KT] 
>MUL=X X 10 X LSI=6 6 6 6 COL=8 8 8 8 OFF=-8 -13 3 -13 -8 4 
>3 4 FORMAT=I3 I3 K3 I3 SEL='DAY 05180; TIME[HMS] 15:45:00 
>15:59:00' DEC=NO LIN=1 MAX ELE=1 MAX TITLE=' '
>
>However, McIDAS kept reporting that "PTDISP: No data found 
>matching search conditions".  I'm not sure why it can't 
>find the data.

The TIME key stored with observations in a McIDAS surface MD file is
the hour of the report only (no minutes, no seconds).  To see
observations recorded for subhour timescales, you need to select based
on the HMS key also found in the file.  Here is your same example
modified to use HMS in the SEL= clause:

PTDISP RTPTSRC/SFCHOURLY 1 PAR=T[F] TD[F] PSL[MB] GUS[KT] 
MUL=X X 10 X LSI=6 6 6 6 COL=8 8 8 8 OFF=-8 -13 3 -13 -8 4 
3 4 FORMAT=I3 I3 K3 I3 SEL='DAY 05180; HMS[HMS] 15:45:00 
15:59:00' DEC=NO LIN=1 MAX ELE=1 MAX TITLE=' '

>It seems that PTDISP can't accept the time 
>format I used.  Is that right?

PTDISP had no problems with the time format you used.  Rather, the TIME
associated with the observations were all on the ordinal hour.

You can convince yourself of this by listing out the observations
using PTLIST:

PTLIST RTPTSRC/SFCHOURLY PAR=T[F] TD[F] PSL[MB] GUS[KT] SEL='DAY 05180; 
HMS[HMS] 15:45:00 15:59:00'

Please say hi to Ward and Stanley for me!

Cheers,

Tom
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