[Met_help] [rt.rap.ucar.edu #61567] History for Bug setting Mercator Scan Mode

[John Halley Gotway via RT]

----------------------------------------------------------------
  Initial Request
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Hello,

I wanted to pass along some information I uncovered after grid_stat 
failed to compare two like Mercator grids.

There is a bug at line 800, character 33 of the data2d_grib2.cc file of 
METv4.0, which sets the scan mode for the Mercator projection. That 
character should be a '5', instead of a '4'.  The line should correctly 
read:
> ScanMode = gfld->igdtmpl[15];

Let me know if you have questions.

Best,

Jordan Gerth
CIMSS/SSEC - Madison, WI


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  Complete Ticket History
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Subject: Re: [rt.rap.ucar.edu #61567] Bug setting Mercator Scan Mode
From: John Halley Gotway
Time: Thu May 30 13:18:42 2013

Jordan,

Thank you very much for letting us know of the problem.  I tried the
change you suggested and did some testing, but unfortunately, I think
the problems are more extensive than that.  So we've
identified a problem in our support for GRIB2 data on a mercator
projection.  We are investigating the issue and will post a bugfix
once we've resolved it.

In the meantime, our support for GRIB1 data on a mercator projection
appears to be fine.  If you need to get going before we have a bugfix
available, you could always convert your data from GRIB2 to
GRIB1 using the cnvgrib utility.

While that change you made enables MET to parse the grid information,
I suspect that if you were to use the plot_data_plane utility within
MET to plot a field of data, you'd probably find that the
grid is not located on the correct place on earth.  For example,
here's how you could run plot_data_plane to plot 2-meter temperature.
Just substitute in your GRIB2 file name:
   METv4.0/bin/plot_data_plane my_file.grb2 tmp_z2.ps 'name="TMP";
level="Z2";'

Thanks,
John Halley Gotway
met_help at ucar.edu

On 05/28/2013 11:52 PM, Jordan Gerth via RT wrote:
>
> Tue May 28 23:52:08 2013: Request 61567 was acted upon.
> Transaction: Ticket created by jordang at ssec.wisc.edu
>         Queue: met_help
>       Subject: Bug setting Mercator Scan Mode
>         Owner: Nobody
>    Requestors: jordang at ssec.wisc.edu
>        Status: new
>   Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=61567 >
>
>
> Hello,
>
> I wanted to pass along some information I uncovered after grid_stat
> failed to compare two like Mercator grids.
>
> There is a bug at line 800, character 33 of the data2d_grib2.cc file
of
> METv4.0, which sets the scan mode for the Mercator projection. That
> character should be a '5', instead of a '4'.  The line should
correctly
> read:
>> ScanMode = gfld->igdtmpl[15];
>
> Let me know if you have questions.
>
> Best,
>
> Jordan Gerth
> CIMSS/SSEC - Madison, WI
>

------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #61567] Bug setting Mercator Scan Mode
From: John Halley Gotway
Time: Mon Jun 03 10:52:59 2013

Jordan,

We worked up a fix for the problems parsing Mercator grid information
from GRIB2 files.  Please apply the latest set of patches for METv4.0,
which can be found here:
    http://www.dtcenter.org/met/users/support/known_issues/METv4.0/index.php

Just follow the instructions at the top of the page.  After you've
recompiled with these patches, please let me know if the Mercator
issues you were seeing are resolved.

Thanks,
John

On 05/30/2013 01:18 PM, John Halley Gotway wrote:
> Jordan,
>
> Thank you very much for letting us know of the problem.  I tried the
change you suggested and did some testing, but unfortunately, I think
the problems are more extensive than that.  So we've
> identified a problem in our support for GRIB2 data on a mercator
projection.  We are investigating the issue and will post a bugfix
once we've resolved it.
>
> In the meantime, our support for GRIB1 data on a mercator projection
appears to be fine.  If you need to get going before we have a bugfix
available, you could always convert your data from GRIB2 to
> GRIB1 using the cnvgrib utility.
>
> While that change you made enables MET to parse the grid
information, I suspect that if you were to use the plot_data_plane
utility within MET to plot a field of data, you'd probably find that
the
> grid is not located on the correct place on earth.  For example,
here's how you could run plot_data_plane to plot 2-meter temperature.
Just substitute in your GRIB2 file name:
>    METv4.0/bin/plot_data_plane my_file.grb2 tmp_z2.ps 'name="TMP";
level="Z2";'
>
> Thanks,
> John Halley Gotway
> met_help at ucar.edu
>
> On 05/28/2013 11:52 PM, Jordan Gerth via RT wrote:
>>
>> Tue May 28 23:52:08 2013: Request 61567 was acted upon.
>> Transaction: Ticket created by jordang at ssec.wisc.edu
>>         Queue: met_help
>>       Subject: Bug setting Mercator Scan Mode
>>         Owner: Nobody
>>    Requestors: jordang at ssec.wisc.edu
>>        Status: new
>>   Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=61567 >
>>
>>
>> Hello,
>>
>> I wanted to pass along some information I uncovered after grid_stat
>> failed to compare two like Mercator grids.
>>
>> There is a bug at line 800, character 33 of the data2d_grib2.cc
file of
>> METv4.0, which sets the scan mode for the Mercator projection. That
>> character should be a '5', instead of a '4'.  The line should
correctly
>> read:
>>> ScanMode = gfld->igdtmpl[15];
>>
>> Let me know if you have questions.
>>
>> Best,
>>
>> Jordan Gerth
>> CIMSS/SSEC - Madison, WI
>>

------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #61567] Bug setting Mercator Scan Mode
From: Jordan Gerth
Time: Wed Jun 05 22:58:28 2013

Hello John,

Thank you for the fix, and for making it available in a timely manner.
Everything appears to be functioning correctly now.

Best,

Jordan Gerth

On 6/3/2013 11:53 AM, John Halley Gotway via RT wrote:
> Jordan,
>
> We worked up a fix for the problems parsing Mercator grid
information from GRIB2 files.  Please apply the latest set of patches
for METv4.0, which can be found here:
>
http://www.dtcenter.org/met/users/support/known_issues/METv4.0/index.php
>
> Just follow the instructions at the top of the page.  After you've
recompiled with these patches, please let me know if the Mercator
issues you were seeing are resolved.
>
> Thanks,
> John
>
> On 05/30/2013 01:18 PM, John Halley Gotway wrote:
>> Jordan,
>>
>> Thank you very much for letting us know of the problem.  I tried
the change you suggested and did some testing, but unfortunately, I
think the problems are more extensive than that.  So we've
>> identified a problem in our support for GRIB2 data on a mercator
projection.  We are investigating the issue and will post a bugfix
once we've resolved it.
>>
>> In the meantime, our support for GRIB1 data on a mercator
projection appears to be fine.  If you need to get going before we
have a bugfix available, you could always convert your data from GRIB2
to
>> GRIB1 using the cnvgrib utility.
>>
>> While that change you made enables MET to parse the grid
information, I suspect that if you were to use the plot_data_plane
utility within MET to plot a field of data, you'd probably find that
the
>> grid is not located on the correct place on earth.  For example,
here's how you could run plot_data_plane to plot 2-meter temperature.
Just substitute in your GRIB2 file name:
>>     METv4.0/bin/plot_data_plane my_file.grb2 tmp_z2.ps 'name="TMP";
level="Z2";'
>>
>> Thanks,
>> John Halley Gotway
>> met_help at ucar.edu
>>
>> On 05/28/2013 11:52 PM, Jordan Gerth via RT wrote:
>>> Tue May 28 23:52:08 2013: Request 61567 was acted upon.
>>> Transaction: Ticket created by jordang at ssec.wisc.edu
>>>          Queue: met_help
>>>        Subject: Bug setting Mercator Scan Mode
>>>          Owner: Nobody
>>>     Requestors: jordang at ssec.wisc.edu
>>>         Status: new
>>>    Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=61567 >
>>>
>>>
>>> Hello,
>>>
>>> I wanted to pass along some information I uncovered after
grid_stat
>>> failed to compare two like Mercator grids.
>>>
>>> There is a bug at line 800, character 33 of the data2d_grib2.cc
file of
>>> METv4.0, which sets the scan mode for the Mercator projection.
That
>>> character should be a '5', instead of a '4'.  The line should
correctly
>>> read:
>>>> ScanMode = gfld->igdtmpl[15];
>>> Let me know if you have questions.
>>>
>>> Best,
>>>
>>> Jordan Gerth
>>> CIMSS/SSEC - Madison, WI
>>>


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