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Re: [idvusers] Plotting NARR Composites

Oops, one should always test, then send. ;-) The last ncml files have absolute paths. Use the ones attached here instead, or just edit out the file:/Users/dmurray/data/grids from the previous ones. 

Don



On 1/28/11 7:28 AM, Don Murray wrote:

Hi Mike-

Since I now work at ESRL, I'll take a stab at this. ;-)

As you mention, one of the IDV's strengths is it's ability to read
multiple formats. And, if a netCDF file is self describing in a standard
convention the the IDV knows, it should be able to read it.

The problem in this case is that the files purport to be CF-1.0
Conventions, but there are a couple of missing attributes. The main
problem is that there are no attributes connecting the u and v variables
to either the lat/lon or the Lambert_Conformal project variable. There
are some other issues (like the long name is screwed up and the time is
wrong). I'll talk to the person in charge of web pages and get this
cleared up.

In the mean time, I've attached a bundle and a couple of ncml files that
will allow you to read in the data and get the attached plot. Save the
bundles and the ncml files in the same directory as the downloaded
netcdf files from the page you pointed to below. Then open the bundle.
In a perfect world, you should just be able to recreate the plot in the
image.

Don

On 1/27/11 4:45 PM, Mike Hardiman wrote:

Hi folks,

For me, one of IDV's strong points has been its ability to work with
numerous data formats -- but I've finally managed to trip it up.

I tried to load up NARR Composite data in netCDF format, taken from the
ESRL web site:

http://ow.ly/3LCt2

The above link shows a plot consisting of mwN 700mb Vector Winds from 3
Dates/Times, using NARR. Towards the bottom there are links to download
the plotted data in netCDF format for both the U and V-wind components.

When downloading these files and trying to load them in IDV, it balks
about not finding any gridded data in them. I've tried several 'file
type' options.

When doing the same thing, except using the NCEP/DOE Reanalysis 2
dataset, I have no problems plotting the netCDF data in IDV:

http://ow.ly/3LCxt

One note on the ESRL website mentions that the NARR data is
pre-projected in Lambert Conformal, and this may be what is tripping up
the IDV (though I thought netCDF was supposed to be self-describing when
it comes to data projections and domains, etc). There are no explicit
instructions from ESRL about using the NARR netCDF data with IDV, but
they do provide tips for other software such as GrADS:

http://www.esrl.noaa.gov/psd/data/narr/format.html

Now, if I download the raw NARR data for individual dates/times in Grib
format, IDV handles it just fine. But ESRL's website makes it easy to
create composites, whereas I would not really know where to start if I
wanted to manually create composites using the Grib data (probably could
figure it out with GrADS, but I'm just not there yet).

Does anyone have a ready-to-go solution to allow NARR composite data
from ESRL to display in IDV?

Thanks,
-Mike Hardiman

National Weather Service
WFO EPZ - El Paso, TX / Santa Teresa, NM

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--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596
http://www.esrl.noaa.gov/psd/people/don.murray/

<?xml version="1.0" encoding="UTF-8"?>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2"; 
location="yycompos.67.165.217.91.27.6.49.1.nc">
  <dimension name="y" length="277" />
  <dimension name="x" length="349" />
  <dimension name="level" length="29" />
  <dimension name="time" length="2" isUnlimited="true" />
  <attribute name="Conventions" value="CF-1.0" />
  <attribute name="title" value="Composite Value" />
  <attribute name="history" value="��" />
  <attribute name="comments" value="Data is from North American Regional 
Reanalysis&#xA;(8x/day).  It consists of most variables interpolated 
to&#xA;pressure surfaces from model (sigma) surfaces." />
  <attribute name="institution" value="National Centers for Environmental 
Prediction" />
  <attribute name="platform" value="Model" />
  <attribute name="references" 
value="http://wwwt.emc.ncep.noaa.gov/mmb/rreanl/index.html&#xA;http://www.esrl.noaa.gov/psd/data/gridded/data.narr.html";
 />
  <attribute name="description" value="Computed from the web page 
http://www.cdc.noaa.gov/data/compsites provided by NOAA/ESRL PSD" />
  <variable name="level" shape="level" type="float">
    <attribute name="units" value="millibar" />
    <attribute name="actual_range" type="float" value="1000.0 100.0" />
    <attribute name="long_name" value="Level" />
    <attribute name="positive" value="down" />
    <attribute name="GRIB_id" type="short" value="100" />
    <attribute name="GRIB_name" value="hPa" />
    <attribute name="axis" value="Z" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="lat" shape="y x" type="float">
    <attribute name="long_name" value="latitude" />
    <attribute name="units" value="degrees_north" />
    <attribute name="standard_name" value="latitude" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="lon" shape="y x" type="float">
    <attribute name="units" value="degrees_east" />
    <attribute name="long_name" value="longitude" />
    <attribute name="standard_name" value="longitude" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="time" shape="time" type="double">
    <attribute name="units" value="hours since 1800-1-1 00:00:0.0" />
    <attribute name="long_name" value="time" />
    <attribute name="actual_range" type="double" value="1569072.0 1569069.0" />
    <attribute name="delta_t" value="0000-00-00 03:00:00" />
    <attribute name="standard_name" value="time" />
    <attribute name="axis" value="T" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="xdist" shape="x" type="float">
    <attribute name="long_name" value="eastward distance from southwest corner 
of domain in projection coordinates" />
    <attribute name="units" value="m" />
  </variable>
  <variable name="ydist" shape="y" type="float">
    <attribute name="long_name" value="northward distance from southwest corner 
of domain in projection coordinates" />
    <attribute name="units" value="m" />
  </variable>
  <variable name="uwnd" shape="time level y x" type="float">
    <attribute name="long_name" value="�" />
    <attribute name="valid_range" type="float" value="-9.0E16 9.0E16" />
    <attribute name="actual_range" type="float" value="-8.9999998E15 
8.9999998E15" />
    <attribute name="units" value="m/s" />
    <attribute name="missing_value" type="float" value="-9.96921E36" />
    <attribute name="_FillValue" type="float" value="-32767.0" />
    <attribute name="precision" type="short" value="2" />
    <attribute name="least_significant_digit" type="short" value="1" />
    <attribute name="var_desc" value="�" />
    <attribute name="dataset" value="NARR" />
    <attribute name="level_desc" value=" 700mb Pressure Level" />
    <attribute name="statistic" value="Composite" />
    <attribute name="parent_stat" value="Other" />
    <attribute name="standard_name" value="Default" />
    <attribute name="coordinates" value="time level lat lon"/>
  </variable>
  <variable name="Lambert_Conformal" shape="" type="int">
    <attribute name="grid_mapping_name" value="lambert_conformal_conic" />
    <attribute name="standard_parallel" type="double" value="50.0 50.0" />
    <attribute name="longitude_of_central_meridian" type="double" 
value="-107.0" />
    <attribute name="latitude_of_projection_origin" type="double" value="50.0" 
/>
    <attribute name="false_easting" type="double" value="5632642.22547" />
    <attribute name="false_northing" type="double" value="4612545.65137" />
  </variable>
</netcdf>


<?xml version="1.0" encoding="UTF-8"?>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2"; 
location="yyvcompos.67.165.217.91.27.6.49.1.nc">
  <dimension name="y" length="277" />
  <dimension name="x" length="349" />
  <dimension name="level" length="29" />
  <dimension name="time" length="2" isUnlimited="true" />
  <attribute name="Conventions" value="CF-1.0" />
  <attribute name="title" value="Composite Value" />
  <attribute name="history" value="��" />
  <attribute name="comments" value="Data is from North American Regional 
Reanalysis&#xA;(8x/day).  It consists of most variables interpolated 
to&#xA;pressure surfaces from model (sigma) surfaces." />
  <attribute name="institution" value="National Centers for Environmental 
Prediction" />
  <attribute name="platform" value="Model" />
  <attribute name="references" 
value="http://wwwt.emc.ncep.noaa.gov/mmb/rreanl/index.html&#xA;http://www.esrl.noaa.gov/psd/data/gridded/data.narr.html";
 />
  <attribute name="description" value="Computed from the web page 
http://www.cdc.noaa.gov/data/compsites provided by NOAA/ESRL PSD" />
  <variable name="level" shape="level" type="float">
    <attribute name="units" value="millibar" />
    <attribute name="actual_range" type="float" value="1000.0 100.0" />
    <attribute name="long_name" value="Level" />
    <attribute name="positive" value="down" />
    <attribute name="GRIB_id" type="short" value="100" />
    <attribute name="GRIB_name" value="hPa" />
    <attribute name="axis" value="Z" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="lat" shape="y x" type="float">
    <attribute name="long_name" value="latitude" />
    <attribute name="units" value="degrees_north" />
    <attribute name="standard_name" value="latitude" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="lon" shape="y x" type="float">
    <attribute name="units" value="degrees_east" />
    <attribute name="long_name" value="longitude" />
    <attribute name="standard_name" value="longitude" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="time" shape="time" type="double">
    <attribute name="units" value="hours since 1800-1-1 00:00:0.0" />
    <attribute name="long_name" value="time" />
    <attribute name="actual_range" type="double" value="1569072.0 1569069.0" />
    <attribute name="delta_t" value="0000-00-00 03:00:00" />
    <attribute name="standard_name" value="time" />
    <attribute name="axis" value="T" />
    <attribute name="coordinate_defines" value="point" />
  </variable>
  <variable name="xdist" shape="x" type="float">
    <attribute name="long_name" value="eastward distance from southwest corner 
of domain in projection coordinates" />
    <attribute name="units" value="m" />
  </variable>
  <variable name="ydist" shape="y" type="float">
    <attribute name="long_name" value="northward distance from southwest corner 
of domain in projection coordinates" />
    <attribute name="units" value="m" />
  </variable>
  <variable name="vwnd" shape="time level y x" type="float">
    <attribute name="long_name" value="�" />
    <attribute name="valid_range" type="float" value="-9.0E16 9.0E16" />
    <attribute name="actual_range" type="float" value="-8.9999998E15 
8.9999998E15" />
    <attribute name="units" value="m/s" />
    <attribute name="missing_value" type="float" value="-9.96921E36" />
    <attribute name="_FillValue" type="float" value="-32767.0" />
    <attribute name="precision" type="short" value="2" />
    <attribute name="least_significant_digit" type="short" value="1" />
    <attribute name="var_desc" value="�" />
    <attribute name="dataset" value="NARR" />
    <attribute name="level_desc" value=" 700mb Pressure Level" />
    <attribute name="statistic" value="Composite" />
    <attribute name="parent_stat" value="Other" />
    <attribute name="standard_name" value="Default" />
    <attribute name="coordinates" value="time level lat lon"/>
  </variable>
  <variable name="Lambert_Conformal" shape="" type="int">
    <attribute name="grid_mapping_name" value="lambert_conformal_conic" />
    <attribute name="standard_parallel" type="double" value="50.0 50.0" />
    <attribute name="longitude_of_central_meridian" type="double" 
value="-107.0" />
    <attribute name="latitude_of_projection_origin" type="double" value="50.0" 
/>
    <attribute name="false_easting" type="double" value="5632642.22547" />
    <attribute name="false_northing" type="double" value="4612545.65137" />
  </variable>
</netcdf>
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