20040923: 20040916: downloading FNEXRAD data by ldm

>From: address@hidden
>Organization: GMU
>Keywords: 200409170126.i8H1QrnJ013028 LDM IDD ldmd.conf pqact.conf

Hi Ying,

>Thanks for your reply!

No worries.

>I would like to have the FNEXRAD data as follows:
>- US National 1-hour Precipitation Totals 
>- US National Storm Total Precipitation 
>
>and NEXRAD  1-hour Precipitation Totals 

OK.

>All these three can be PNG-compress format.

For reference, the NEXRAD Level III 1-hour precipitation totals
are not in PNG compressed format.  Rather, they are distributed
in the IDD just like they are in the NWS NOAAPORT broadcast: 
zlib compressed in

>Can you provide scripts for pqact.conf? 

1) NEXRAD 1-hr precipitation totals in broadcast zlib-compresed format:

LDM request of NEXRAD feed for _just_ the 1-hr precip totals:

request NNEXRAD "/pN1P" upstream_IDD_feed_host

example pqact.conf action:

# Use this action to file everything
NEXRAD  ^SDUS[2357]. .... ([0-3][0-9])([0-2][0-9])([0-6][0-9]).*/p(N1P)(...)
        FILE    -close
        data/gempak/nexrad/NIDS/\5/\4/\4_(\1:yyyy)(\1:mm)\1_\2\3


2) FNEXRAD National 1-hour Precipitation Totals
           National Storm Total Precipitation

LDM request of FNEXRAD feed for _just_ the 1-hr and storm total precip
products:

request FNEXRAD "n.p"   upstream_IDD_feed_host

example pqact.conf action:

# NEXRAD Level III radar composites in PNG-compressed GINI format
FNEXRAD ^rad/NEXRCOMP/(...)/(n.p)_(........)_(....)
        FILE    -close
        data/gempak/nexrad/NEXRCOMP/\1/\2/\2_\3_\4


The best way to learn how to create patterns that select specific
products for action is to play with the LDM 'notifyme' command.
For instance, here is a 'notifyme' invocation that will list all
FNEXRAD products being received by your upstream_IDD_feed_host
in the last hour:

notifyme -vxl- -f FNEXRAD -o 3600 -h upstream_IDD_feed_host

Here is a refinement of the same command invocation that will list out
just those products that match the regular expression 'n.p' somewhere
in their header:

notifyme -vxl- -f FNEXRAD -o 3600 -h upstream_IDD_feed_host -p "n.p"

By playing with the patterns specified by the value of the '-p' flag,
you can figure out the simplest regular expression that will match
the products you want to receive (as per request line(s) in ldmd.conf)
and/or process (as per action lines in pqact.conf).

Remember:  after editing pqact.conf, check to make sure that you 
have not made a syntax error:

ldmadmin pqactcheck

Furthermore, you can modify pqact.conf and have your modifications
take effect without stopping and restarting the LDM:

<ldm is running>
edit etc/pqact.conf
ldmadmin pqactcheck         <- check for syntax errors
ldmadmin pqactHUP           <- tell pqact to reread pqact.conf

>Thanks again,

No worries.

Cheers,

Tom
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