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20010516: NEXRAD data (cont.)

>From: "Wayne Bresky" <address@hidden>
>Organization: ?
>Keywords: 200105161402.f4GE2Jp07535


>I am taking over (from Jim Marco who has already left) as the site
>coordinator for the Cornell Meteorology Department.  I am remotely
>monitoring the site from home, hence the unfamiliar email address.

OK.  I _should_ have remembered this, but ...  I too am answering this
from home (ADSL connection at 1285 Kb!).

Wait a minute.  Your request line for NNEXRAD data was from
snow.cit.cornell.edu.  If you are at Cornell, why do you have an LDM
that is feeding from Cornell.  I am confused (not an unusual situation

>Anyway, I think I have a handle on what needs to be done thanks to your
>lengthy and very helpful responses.  I can confirm that the local data
>stream contains NEXRAD images (I checked with the notifyme command as
>you suggested).

Good.  I am taking this to mean that the notifyme to the local host
shows products arriving.

>Apparently, though, Jim left before setting things up properly.

I am suprised about this.  My interactions with Jim were always very
positive and he stuck me as being very competent and thorough.

>I need to ask a clarifying question.  What is the format of the NEXRAD
>data?  McIDAS AREA files?

The NEXRAD data is zlib-compressed "chunks".

>Is this data readily used with McIDAS?

Yes.  The current release of McIDAS supports direct access to these
data through ADDE.  The job of getting things working on your side
would be:

o download and install the current Unidata McIDAS-X addendum (announced
  yesterday; if you are not on the mcidas-x email list, you should sign

o get the ingestion and filing (and scouring!!) of the data working on
  your system

o setup ADDE access to the data files filed by the LDM

>I intend to modify ldmd.conf as you suggested, limiting the requests to
>a handfull of stations.


>After doing this, I will edit the action file
>to file the data away in an appropriate place.

OK, sounds good.

>Before turning on the
>data, though, I wanted to know about the format.  If the data is in a
>format McIDAS can use right away (without running any decoders) then I
>believe I can muddle through the setup without bothering you further.

You do not have to decode the data into AREA file format.  On top of
that, the nids2area decoder in the ldm-mcidas package does NOT (yet)
work with the zlib-compressed NEXRAD images available through
NOAAPORT/IDD.  It works on the uncompressed NIDS files that one could
get directly from WSI Corporation.  Since the data is freely available
now, you no longer need worry about that data.

>Thanks again.

You are welcome.  Please don't hesitate to ask questions while setting
up access to the NEXRAD data.  In the long run it is easier for me to
help out on the front end (i.e., setup) than on the back end (i.e.,
finding out what is going/went wrong).


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