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

20000203: Bad "Lo2 - Longitude of last grid point" in MERCator GINI sectors

>From: Unidata User Support <address@hidden>
>Organization: Unidata Program Center
>Keywords: 200002031940.MAA04384 GINI navigation

Hi Barb,

We have noticed that the Lo2 parameter in the GINI Puerto Rico and
Hawaii regional sectors has an incorrect sign.  This situation started
sometime after Tuesday evening (I don't know exactly when it may have
started since I was not looking at the imagery yesterday).

The values I am unpacking from the headers look like:

Puerto Rico Regional VIS, 3.9 um, 10.7 um, 12.0 um (I didn't check the WV):

lat1: 9.000000  lon1: -77.000000
lat2: 25.665000  lon2: 59.459000

Hawaii Regional VIS, 3.9 um, 10.7 um, 12.0 um (I didn't check the WV):

lat1: 9.343000  lon1: -167.315000
lat2: 28.083600  lon2: 145.878000

You can see from these that the sign of the longitude for the "last grid
point" is inverted from what it should be.

As an aside comment, AWIPS workstations will not notice this error
since their display code does not use the LAT,LON pairs in the header
to do navigation.  GEMPAK/N-AWIPS does not see this problem since it
has a rudimentary sanity check in unpacking the LAT,LON points.  If the
sign of the last grid point longitude looks wrong, it gets changed to
look correct.  The problem is only seen by us poor shmos that are
assuming that the header information that we are trying to use is
correct.

Thanks in advance for any help you can provide on this.

Tom Yoksas

>From address@hidden  Mon Feb  7 11:40:49 2000
>Date: Mon, 7 Feb 2000 13:40:37 -0500
>Subject: Incident notification from Help!

Thank you for your request for help.  A technician will be contacting you.

Your call tracking number is PROO-4GAPMF
Your problem has been recorded as: Positive values versus negative values
reported within the longitudinal parameters contained in the Product
Definition Block of the AWIPS header information.   Reported problem
confirmed by PRC software personnel.

>From address@hidden  Mon Feb  7 12:00:22 2000
>From: address@hidden
To: address@hidden, address@hidden
>cc: address@hidden, address@hidden,
>        address@hidden, address@hidden,
>        address@hidden, address@hidden
>Date: Mon, 7 Feb 2000 14:00:12 -0500
>Subject: Re: 20000203: Bad "Lo2 - Longitude of last grid point" in
>        MERCator GINI sectors


Shift Supervisor -

Please open a new Help Desk trouble ticket and assign it to Pat Otero.  The
problem is for the nport2 (currently GINI prime ) machine but is not
occurring on nport1 (currently GINI backup) - only some (LON1 out of LON1 &
LON2) GINI Product header Longitude Values are being reported/recorded as
negative values in the GINI-2 product headers.  Unidata users have reported
seeing this problem since operations were switched from nport1 to nport2 on
the Hawaii and Puerto Rico sectors (see below).  You can attach/incorporate
this email into the work section for the trouble ticket.

- Barb

>From address@hidden  Tue Feb  8 10:57:06 2000
To: address@hidden
Date: Tue, 8 Feb 2000 12:56:52 -0500
Subject: Incident notification from Help!

Your Incident ticket is considered closed.  If you think the problem still
exists please call the help desk.

The original problem was:
Positive values versus negative values reported in the longitudinal
parameters contained within the Product Definition Block of the AWIPS
header information.   Reported problem confirmed by PRC software personnel.