[Met_help] [rt.rap.ucar.edu #64869] History for NetCDF Header information for Latitude-Longitude Projection
John Halley Gotway via RT
met_help at ucar.edu
Tue Feb 18 12:03:23 MST 2014
----------------------------------------------------------------
Initial Request
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Hi,
I am using MODE. I am using this with climatological grids, so I don't have forecast and observation grids. I am analyzing the same grid as if it were both to perform climatological analysis.
I obtained an example netcdf file that is the result of the PCP-combine tool. The example I found is from WRF on a Lambert Conformal grid. It had the following global variables to create the lat/lon of the grid:
:MET_version = "V3.0" ;
:MET_tool = "mode" ;
:Projection = "Lambert Conformal" ;
:scale_lat_1 = "25.187500" ;
:scale_lat_2 = "25.187500" ;
:lat_pin = "25.187500" ;
:lon_pin = "-124.687500" ;
:x_pin = "0.000000" ;
:y_pin = "0.000000" ;
:lon_orient = "-124.687500" ;
:d_km = "12.000000" ;
:r_km = "6367.470000" ;
Is there an example cdl file that would have the global variables for a Latitude-Longitude grid?
Chris
----------------------------------------------------------------------------------------------------------------------------------
Nothing is so astonishing in education as the amount of ignorance it accumulates in the form of inert facts.
--- Henry Adams
----------------------------------------------------------------------------------------------------------------------------------
Christopher J. Anderson, PhD
Research Assistant Professor
Assistant Director, ISU Climate Science Program
Iowa State University
Office: 515-294-9948
Fax: 515-294-2619
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
Irrationality cannot be fought with empirical evidence. --- Jon Stewart
Scientific Evidence of Jon Stewart's observation: http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-fin_b_3932273.html
----------------------------------------------------------------
Complete Ticket History
----------------------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #64869] NetCDF Header information for Latitude-Longitude Projection
From: John Halley Gotway
Time: Tue Jan 14 16:39:15 2014
Hello Chris,
I apologize for the delay in getting back to you.
I see that you're running the METv3.0 version of MODE. I want to
mention that there was a significant bug in the reporting of object
area sizes found and fixed in METv4.1. This is discussed in the
METv4.1 release notes. If you have the option, I'd suggest updating
to METv4.1:
http://www.dtcenter.org/met/users/support/release_notes/METv4.1_release_notes.php
I see that you're looking for a CDL file with an example of the global
grid attributes for a lat/lon grid. Here's how you can go about
getting that information:
(1) Run copygb to regrid a sample GRIB file to a lat/lon grid. I just
found a lat/lon grid in use by NCEP:
http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html
Grid 4 is a global 0.5 degree lat/lon grid:
copygb -xg4
METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
grid4.grb
(2) Run pcp_combine to generate a NetCDF file:
METv3.0/bin/pcp_combine -add grid4.grb 12 apcp_12.nc
(3) Run ncdump -h to look at the header:
ncdump -h apcp_12.nc
And here's the resulting global grid attributes:
:Projection = "LatLon" ;
:lat_ll = "-90.000000 degrees_north" ;
:lon_ll = "0.000000 degrees_east" ;
:delta_lat = "0.500000 degrees" ;
:delta_lon = "0.500000 degrees" ;
:Nlat = "361 grid_points" ;
:Nlon = "720 grid_points" ;
lat_ll and lon_ll are the latitude and longitude of the lower-left
point of the grid. delta_lat and delta_lon define the grid spacing in
degrees. And Nlat and Nlon specify the number of grid points
in each direction. Note that these are defined and parsed as strings
rather than numbers.
Hope that helps clarify.
Just let me know if you have any more questions.
Thanks,
John Halley Gotway
met_help at ucar.edu
On 01/10/2014 02:43 PM, Anderson, Christopher [AGRON] via RT wrote:
>
> Fri Jan 10 14:43:39 2014: Request 64869 was acted upon.
> Transaction: Ticket created by cjames at iastate.edu
> Queue: met_help
> Subject: NetCDF Header information for Latitude-Longitude
Projection
> Owner: Nobody
> Requestors: cjames at iastate.edu
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=64869 >
>
>
> Hi,
>
> I am using MODE. I am using this with climatological grids, so I
don't have forecast and observation grids. I am analyzing the same
grid as if it were both to perform climatological analysis.
>
> I obtained an example netcdf file that is the result of the PCP-
combine tool. The example I found is from WRF on a Lambert Conformal
grid. It had the following global variables to create the lat/lon of
the grid:
>
> :MET_version = "V3.0" ;
> :MET_tool = "mode" ;
> :Projection = "Lambert Conformal" ;
> :scale_lat_1 = "25.187500" ;
> :scale_lat_2 = "25.187500" ;
> :lat_pin = "25.187500" ;
> :lon_pin = "-124.687500" ;
> :x_pin = "0.000000" ;
> :y_pin = "0.000000" ;
> :lon_orient = "-124.687500" ;
> :d_km = "12.000000" ;
> :r_km = "6367.470000" ;
>
>
> Is there an example cdl file that would have the global variables
for a Latitude-Longitude grid?
>
>
> Chris
>
>
>
>
----------------------------------------------------------------------------------------------------------------------------------
> Nothing is so astonishing in education as the amount of ignorance it
accumulates in the form of inert facts.
> --- Henry Adams
>
----------------------------------------------------------------------------------------------------------------------------------
> Christopher J. Anderson, PhD
> Research Assistant Professor
> Assistant Director, ISU Climate Science Program
> Iowa State University
> Office: 515-294-9948
> Fax: 515-294-2619
>
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
>
> Irrationality cannot be fought with empirical evidence. --- Jon
Stewart
> Scientific Evidence of Jon Stewart's observation:
http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-
fin_b_3932273.html
>
------------------------------------------------
Subject: RE: [rt.rap.ucar.edu #64869] NetCDF Header information for Latitude-Longitude Projection
From: Anderson, Christopher [AGRON]
Time: Thu Jan 23 13:21:38 2014
Hello,
Thanks much for your detailed response. I have only one question:
The counting error for size of MODE objects is only evident in the
summary text files, correct?
Same question, stated another way:
MODE isn't extracting areas that are too large; it is counting the
gridpoints of the extracted areas incorrectly, correct?
The reason I ask is that I work with the netcdf files and its contents
(fcst_obj_raw). So, if I understand correctly, I can count the
gridpoints in the netcdf files myself and avoid the error in the text
summary files produced by MODE.
Chris
----------------------------------------------------------------------------------------------------------------------------------
Nothing is so astonishing in education as the amount of ignorance it
accumulates in the form of inert facts.
--- Henry Adams
----------------------------------------------------------------------------------------------------------------------------------
Christopher J. Anderson, PhD
Research Assistant Professor
Assistant Director, ISU Climate Science Program
Iowa State University
Office: 515-294-9948
Fax: 515-294-2619
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
Irrationality cannot be fought with empirical evidence. --- Jon
Stewart
Scientific Evidence of Jon Stewart's observation:
http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-
fin_b_3932273.html
________________________________________
From: John Halley Gotway via RT [met_help at ucar.edu]
Sent: Tuesday, January 14, 2014 5:39 PM
To: Anderson, Christopher [AGRON]
Subject: Re: [rt.rap.ucar.edu #64869] NetCDF Header information for
Latitude-Longitude Projection
Hello Chris,
I apologize for the delay in getting back to you.
I see that you're running the METv3.0 version of MODE. I want to
mention that there was a significant bug in the reporting of object
area sizes found and fixed in METv4.1. This is discussed in the
METv4.1 release notes. If you have the option, I'd suggest updating
to METv4.1:
http://www.dtcenter.org/met/users/support/release_notes/METv4.1_release_notes.php
I see that you're looking for a CDL file with an example of the global
grid attributes for a lat/lon grid. Here's how you can go about
getting that information:
(1) Run copygb to regrid a sample GRIB file to a lat/lon grid. I just
found a lat/lon grid in use by NCEP:
http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html
Grid 4 is a global 0.5 degree lat/lon grid:
copygb -xg4
METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
grid4.grb
(2) Run pcp_combine to generate a NetCDF file:
METv3.0/bin/pcp_combine -add grid4.grb 12 apcp_12.nc
(3) Run ncdump -h to look at the header:
ncdump -h apcp_12.nc
And here's the resulting global grid attributes:
:Projection = "LatLon" ;
:lat_ll = "-90.000000 degrees_north" ;
:lon_ll = "0.000000 degrees_east" ;
:delta_lat = "0.500000 degrees" ;
:delta_lon = "0.500000 degrees" ;
:Nlat = "361 grid_points" ;
:Nlon = "720 grid_points" ;
lat_ll and lon_ll are the latitude and longitude of the lower-left
point of the grid. delta_lat and delta_lon define the grid spacing in
degrees. And Nlat and Nlon specify the number of grid points
in each direction. Note that these are defined and parsed as strings
rather than numbers.
Hope that helps clarify.
Just let me know if you have any more questions.
Thanks,
John Halley Gotway
met_help at ucar.edu
On 01/10/2014 02:43 PM, Anderson, Christopher [AGRON] via RT wrote:
>
> Fri Jan 10 14:43:39 2014: Request 64869 was acted upon.
> Transaction: Ticket created by cjames at iastate.edu
> Queue: met_help
> Subject: NetCDF Header information for Latitude-Longitude
Projection
> Owner: Nobody
> Requestors: cjames at iastate.edu
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=64869 >
>
>
> Hi,
>
> I am using MODE. I am using this with climatological grids, so I
don't have forecast and observation grids. I am analyzing the same
grid as if it were both to perform climatological analysis.
>
> I obtained an example netcdf file that is the result of the PCP-
combine tool. The example I found is from WRF on a Lambert Conformal
grid. It had the following global variables to create the lat/lon of
the grid:
>
> :MET_version = "V3.0" ;
> :MET_tool = "mode" ;
> :Projection = "Lambert Conformal" ;
> :scale_lat_1 = "25.187500" ;
> :scale_lat_2 = "25.187500" ;
> :lat_pin = "25.187500" ;
> :lon_pin = "-124.687500" ;
> :x_pin = "0.000000" ;
> :y_pin = "0.000000" ;
> :lon_orient = "-124.687500" ;
> :d_km = "12.000000" ;
> :r_km = "6367.470000" ;
>
>
> Is there an example cdl file that would have the global variables
for a Latitude-Longitude grid?
>
>
> Chris
>
>
>
>
----------------------------------------------------------------------------------------------------------------------------------
> Nothing is so astonishing in education as the amount of ignorance it
accumulates in the form of inert facts.
> --- Henry Adams
>
----------------------------------------------------------------------------------------------------------------------------------
> Christopher J. Anderson, PhD
> Research Assistant Professor
> Assistant Director, ISU Climate Science Program
> Iowa State University
> Office: 515-294-9948
> Fax: 515-294-2619
>
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
>
> Irrationality cannot be fought with empirical evidence. --- Jon
Stewart
> Scientific Evidence of Jon Stewart's observation:
http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-
fin_b_3932273.html
>
------------------------------------------------
Subject: RE: [rt.rap.ucar.edu #64869] NetCDF Header information for Latitude-Longitude Projection
From: John Halley Gotway
Time: Thu Jan 23 16:08:24 2014
Yes, that's correct. If you look at the NetCDF object files from MODE
and
look at the fcst_obj_id and obs_obj_id and count up the number of grid
points with each object ID number, those areas are accurate.
We found this bug by realizing that counting up the object id's in the
NetCDF files didn't match the ASCII output.
So you should be set.
Thanks,
John
>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=64869 >
>
> Hello,
>
> Thanks much for your detailed response. I have only one question:
>
> The counting error for size of MODE objects is only evident in the
summary
> text files, correct?
>
> Same question, stated another way:
>
> MODE isn't extracting areas that are too large; it is counting the
> gridpoints of the extracted areas incorrectly, correct?
>
> The reason I ask is that I work with the netcdf files and its
contents
> (fcst_obj_raw). So, if I understand correctly, I can count the
gridpoints
> in the netcdf files myself and avoid the error in the text summary
files
> produced by MODE.
>
> Chris
>
>
>
----------------------------------------------------------------------------------------------------------------------------------
> Nothing is so astonishing in education as the amount of ignorance it
> accumulates in the form of inert facts.
> --- Henry Adams
>
----------------------------------------------------------------------------------------------------------------------------------
> Christopher J. Anderson, PhD
> Research Assistant Professor
> Assistant Director, ISU Climate Science Program
> Iowa State University
> Office: 515-294-9948
> Fax: 515-294-2619
>
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
>
> Irrationality cannot be fought with empirical evidence. --- Jon
Stewart
> Scientific Evidence of Jon Stewart's observation:
> http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-
fin_b_3932273.html
> ________________________________________
> From: John Halley Gotway via RT [met_help at ucar.edu]
> Sent: Tuesday, January 14, 2014 5:39 PM
> To: Anderson, Christopher [AGRON]
> Subject: Re: [rt.rap.ucar.edu #64869] NetCDF Header information for
> Latitude-Longitude Projection
>
> Hello Chris,
>
> I apologize for the delay in getting back to you.
>
> I see that you're running the METv3.0 version of MODE. I want to
mention
> that there was a significant bug in the reporting of object area
sizes
> found and fixed in METv4.1. This is discussed in the
> METv4.1 release notes. If you have the option, I'd suggest updating
to
> METv4.1:
>
http://www.dtcenter.org/met/users/support/release_notes/METv4.1_release_notes.php
>
> I see that you're looking for a CDL file with an example of the
global
> grid attributes for a lat/lon grid. Here's how you can go about
getting
> that information:
>
> (1) Run copygb to regrid a sample GRIB file to a lat/lon grid. I
just
> found a lat/lon grid in use by NCEP:
> http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html
> Grid 4 is a global 0.5 degree lat/lon grid:
> copygb -xg4
> METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
grid4.grb
>
> (2) Run pcp_combine to generate a NetCDF file:
> METv3.0/bin/pcp_combine -add grid4.grb 12 apcp_12.nc
>
> (3) Run ncdump -h to look at the header:
> ncdump -h apcp_12.nc
>
> And here's the resulting global grid attributes:
> :Projection = "LatLon" ;
> :lat_ll = "-90.000000 degrees_north" ;
> :lon_ll = "0.000000 degrees_east" ;
> :delta_lat = "0.500000 degrees" ;
> :delta_lon = "0.500000 degrees" ;
> :Nlat = "361 grid_points" ;
> :Nlon = "720 grid_points" ;
>
> lat_ll and lon_ll are the latitude and longitude of the lower-left
point
> of the grid. delta_lat and delta_lon define the grid spacing in
degrees.
> And Nlat and Nlon specify the number of grid points
> in each direction. Note that these are defined and parsed as
strings
> rather than numbers.
>
> Hope that helps clarify.
>
> Just let me know if you have any more questions.
>
> Thanks,
> John Halley Gotway
> met_help at ucar.edu
>
>
> On 01/10/2014 02:43 PM, Anderson, Christopher [AGRON] via RT wrote:
>>
>> Fri Jan 10 14:43:39 2014: Request 64869 was acted upon.
>> Transaction: Ticket created by cjames at iastate.edu
>> Queue: met_help
>> Subject: NetCDF Header information for Latitude-Longitude
>> Projection
>> Owner: Nobody
>> Requestors: cjames at iastate.edu
>> Status: new
>> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=64869 >
>>
>>
>> Hi,
>>
>> I am using MODE. I am using this with climatological grids, so I
don't
>> have forecast and observation grids. I am analyzing the same grid
as if
>> it were both to perform climatological analysis.
>>
>> I obtained an example netcdf file that is the result of the PCP-
combine
>> tool. The example I found is from WRF on a Lambert Conformal grid.
It
>> had the following global variables to create the lat/lon of the
grid:
>>
>> :MET_version = "V3.0" ;
>> :MET_tool = "mode" ;
>> :Projection = "Lambert Conformal" ;
>> :scale_lat_1 = "25.187500" ;
>> :scale_lat_2 = "25.187500" ;
>> :lat_pin = "25.187500" ;
>> :lon_pin = "-124.687500" ;
>> :x_pin = "0.000000" ;
>> :y_pin = "0.000000" ;
>> :lon_orient = "-124.687500" ;
>> :d_km = "12.000000" ;
>> :r_km = "6367.470000" ;
>>
>>
>> Is there an example cdl file that would have the global variables
for a
>> Latitude-Longitude grid?
>>
>>
>> Chris
>>
>>
>>
>>
----------------------------------------------------------------------------------------------------------------------------------
>> Nothing is so astonishing in education as the amount of ignorance
it
>> accumulates in the form of inert facts.
>> --- Henry Adams
>>
----------------------------------------------------------------------------------------------------------------------------------
>> Christopher J. Anderson, PhD
>> Research Assistant Professor
>> Assistant Director, ISU Climate Science Program
>> Iowa State University
>> Office: 515-294-9948
>> Fax: 515-294-2619
>>
http://climate.engineering.iastate.edu/ResearchTeam/AndersonChristopher.html
>>
>> Irrationality cannot be fought with empirical evidence. --- Jon
>> Stewart
>> Scientific Evidence of Jon Stewart's observation:
>> http://www.huffingtonpost.com/marty-kaplan/most-depressing-brain-
fin_b_3932273.html
>>
>
>
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