20050816: McIDAS - ANM GRIB file decoding

>From: "Oana" <address@hidden>
>Organization: National Administration of Meteorology
>Keywords: 200508090846.j798kTjo016776 McIDAS-XCD gribdec

Hi Oana,

I apologize for taking so long to get back to you.  Last week was more
busy than I had expected.

re:
>So, I will wait for you to modify the gribdec.

I just found the problem in the 'gribdec' code that was causing the
location for the Aladin grib messages to be decoded incorrectly.  The
error was very silly indeed.  In a block of code that checks the
scanning mode of the values in the grib message, there was an error
that was preventing grids east of 0 longitude from being interpreted
correctly:

(The next section is mostly for the tracking system; it won't mean much
to you at the moment since you are not using gribdec code yet.)

In the section for cylindrical equidistant grids in btab.c, I made the
following code changes:

change:
        if ( !mode&0x40 ) {

to:

        if ( !(mode&0x40) ) {


and change:

        if ( !mode&0x80 ) {

to:

        if ( !(mode&0x80) ) {


After making this code change, I am able to convert the Aladin and SAF
GRIB messages you gave me into McIDAS grids and plot them using the
McIDAS GRDDISP routine.  I will be producing an updated gribdec.tar.Z
distribution after I do some more testing.

>I have another three questions for you:
>- how can I get the mcidas 2005?

If you havn't already done so, please register as a Unidata user:

http://www.unidata.ucar.edu/user.php?op=new_user

After you are registered, please let me (Unidata User Support) so that
we can get you (ANM) added into the exceptions list for McIDAS
downloads.  We are granting you access to the Unidata McIDAS-X
distribution because of your stated intention of using McIDAS in the
degree granting program run by the National Administration of
Meteorology of Romania.

Please note: If you do not intend to use this in your education
program, you will be required to get McIDAS directly from the Space
Science and Engineering Center (SSEC) at the University of
Wisconsin-Madison.  This would require that you join the McIDAS Users
Group (MUG) operated by SSEC and play yearly MUG fees.

Also please note that if you decided that you want to access datasets
maintained by SSEC, you will need to join the MUG.

Finally, I must add that if SSEC declares that they don't consider your
use of McIDAS to be compatible with our license to distribute the
software then you will be forced to join the MUG.  I don't believe that
this will be the case since we are providing our McIDAS distribution
for use in your educational facility.

As soon as your are a registered Unidata user and we have added NAM
to our exection list for McIDAS, I will provide you with the necessary
information for you to get the gribdec distribution that you need to
convert your GRIB messages into McIDAS GRIDs.

>- is the Unidata McIDAS-X Training Workshop going to be a pdf file on your 
>  web page?

Yes it will.  I will be working on the PDF version of the Training
Workshop and Users Guide very soon (it is near the top of my list of
things to do).

>- how can I display a RGB image: I want to put it like this ex: R= band 3, 
>  G= band 2, B= band 1 of the MSG image.

I see from the email you sent after this one that you figured out how
to do this (using COMBINE).

>From address@hidden  Thu Aug 11 07:52:19 2005

>I did the RGB. Sorry for keep bothering you!

Your emails were not a bother.  I am just sorry that I couldn't attend to
the decoding problem before today.

>Thank you!

No worries,

Cheers,

Tom
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