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Re: attached file
- Subject: Re: attached file
- Date: Thu, 18 Oct 2007 12:53:27 -0600
Noman,
We are continuing to track down this problem and there may be a
fix for it in at least some of the cases where the original files were in grib
format with polar stereographic projections. We'll let you know when
we come up with something.
In the meantime, I hope you can put together a workaround via the
information John gave you.
-- Ben
On 10/18/07, Nawajish Noman
<
address@hidden> wrote:John,
Thanks for the clarifications.
Noman
-----Original Message-----
From: John Caron [mailto:address@hidden]
Sent:
Wednesday, October 17, 2007 12:08 PM
To: Ben Domenico
Cc: Nawajish Noman;
address@hidden
Subject: Re: attached
file
Hi Noman:
Unfortunately its common for these files to not
follow the
conventions
exactly.
"longitude_of_projection_origin"
should be
"straight_vertical_longitude_from_pole". Its a common error, and
we tend
to try to be lenient in these cases, so our software would probably
look
for both names.
Ben, can we notify the writer? Also, can I get a
sample of the file for
my tests?
John
Ben Domenico wrote:
>
Noman,
>
> I'm forwarding this message to John Caron who can
help you with the
> details of the projection in that netCDF
file.
>
> -- Ben
>
> On 10/16/07, * Nawajish Noman* <address@hidden
> <mailto:address@hidden>>
wrote:
>
> Hi Ben,
>
> We are working on the problem with
Polar stereographic projection.
I
> am
comparing the grid_mapping parameters in the file (see
your
email
> below) and the parameters listed
on the CF Convention page at _
>
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.0/cf-conventions.htm
l#appendix-grid-mappings_
>
Example
F.5.
>
> *Example F.5. Polar
stereographic*
>
> grid_mapping_name =
polar_stereographic
>
>
>
>
*/Map parameters:/*
>
>
straight_vertical_longitude_from_pole
>
> latitude_of_projection_origin - Either
+90. or -90.
>
> Either standard_parallel
or scale_factor_at_projection_origin
>
>
false_easting
>
> false_northing
>
> *Parameters in file
are:***
>
> char
Polar_Stereographic_projection_Grid;
>
> :grid_mapping_name
=
"polar_stereographic";
>
> :longitude_of_projection_origin
= -
105.0; //
double
>
> :scale_factor_at_projection_origin
= 0.933; // double
>
> Here are my
questions:
>
> Q1: Some of the parameters
are missing in file. What do we do
about
> missing
parameters?
>
> Q2: You have "
longitude_of_projection_origin " in file but the
CF
> convention says "
latitude_of_projection_origin" - What do with
> "longitude_of_projection_origin
"?
>
> We look for parameters listed
in CF Conventions and map them to
our
>
Spatial reference parameters. If parameters are missing in file we
> assume default value. If incorrect parameters
are specified - we
> ignore
them.
>
> I want to make sure we are
reading the parameters from your file
>
correctly. Please comment...
>
>
Thanks,
>
>
Noman
>
> -----Original
Message-----
> From: address@hidden <mailto:
address@hidden> [
> mailto:address@hidden] On Behalf Of Ben
Domenico
> Sent: Tuesday, June 05, 2007 1:56
PM
> To: Steve Kopp
> Cc: Nawajish Noman
>
Subject: Re: attached file
>
>
Steve,
>
> I'll attach jpegs of the
dataset as displayed in arcMap and
one
from
>
> the IDV. In each
case, you can see at the bottom of the screen,
the
>
> lat/lon values associated with
the cursor position. I'll
also
append
>
> the ncDump output which
shows the projection information --
in
netCDF
>
> terms (
i.e., Polar_Stereographic_projection_Grid)
anyway.
>
> --
Ben
>
> ncDump
output
>
>
===================================================
>
>
netcdf C:/Documents and
>
Settings/ben/Desktop/ST4.2006010100.06hWithLatLon.nc
{
>
> dimensions:
>
> time
= 1; // (has
coord.var)
>
> y =
815; // (has
coord.var)
>
> x =
1121; // (has
coord.var)
>
> variables:
>
> float
Total_precipitation(time=1, y=815,
x=1121);
>
> :units
=
"kg/m^2";
>
> :long_name
= "Total precipitation @ surface";
>
> :missing_value
= -9999.0f; //
float
>
> :grid_mapping
=
"Polar_Stereographic_projection_Grid";
>
> :GRIB_param_name
= "Total precipitation";
>
> :GRIB_center_id
= 7; //
int
>
> :GRIB_table_id
= 2; //
int
>
> :GRIB_param_number
= 61; //
int
>
> :GRIB_param_id
= 1, 7, 2, 61; // int
>
> :GRIB_product_definition_type
=
"Accumulation";
>
> :GRIB_level_type
= 1; // int
>
> int
time(time=1);
>
> :long_name
= "forecast time";
>
> :units
= "hour since
2005-12-31T12:00:00Z";
>
> :GRIB_orgReferenceTime
=
"2005-12-31T12:00:00Z";
>
> :GRIB2_significanceOfRTName
= "Start of forecast";
>
> :_CoordinateAxisType
=
"Time";
>
> double
y(y=815);
>
> :units
=
"km";
>
> :long_name
= "y coordinate of projection";
>
> :standard_name
=
"projection_y_coordinate";
>
> :grid_spacing
= "4.763
km";
>
> :_CoordinateAxisType
=
"GeoY";
>
> double
x(x=1121);
>
> :units
=
"km";
>
> :long_name
= "x coordinate of
projection";
>
> :standard_name
=
"projection_x_coordinate";
>
> :grid_spacing
= "
4.763
km";
>
> :_CoordinateAxisType
=
"GeoX";
>
> char
Polar_Stereographic_projection_Grid;
>
> :grid_mapping_name
= "polar_stereographic";
>
> :longitude_of_projection_origin
= -105.0; //
double
>
> :scale_factor_at_projection_origin
= 0.933; //
double
>
> :earth_shape
= "spherical";
>
> :GRIB_param_Dx
= 4763.0; //
double
>
> :GRIB_param_Dy
= 4763.0; //
double
>
> :GRIB_param_GDSkey
= 1294122487; //
int
>
> :GRIB_param_La1
=
23.117; //
double
>
> :GRIB_param_Lo1
= -119.023; //
double
>
> :GRIB_param_LoV
= -105.0; //
double
>
> :GRIB_param_Nx
= 1121; //
int
>
> :GRIB_param_Ny
= 881; // int
>
> :GRIB_param_ProjFlag
= 0; //
int
>
> :GRIB_param_ResCompFlag
= 8; //
int
>
> :GRIB_param_ScanningMode
= 64; //
int
>
> :GRIB_param_grid_name
= "Polar Stereographic projection
Grid";
>
> :GRIB_param_grid_radius_spherical_earth
= 6367.47; //
double
>
> :GRIB_param_grid_shape
=
"spherical";
>
> :GRIB_param_grid_shape_code
= 0; // int
>
> :GRIB_param_grid_type
= 5; //
int
>
> :_CoordinateTransformType
=
"Projection";
>
> :_CoordinateAxisTypes
= "GeoX
GeoY";
>
> double
lat(y=815, x=1121);
>
> :units
=
"degrees_north";
>
> :long_name
= "latitude
coordinate";
>
> :standard_name
=
"latitude";
>
> :_CoordinateAxisType
= "Lat";
>
> double
lon(y=815,
x=1121);
>
> :units
=
"degrees_east";
>
> :long_name
= "longitude
coordinate";
>
> :standard_name
= "longitude";
>
> :_CoordinateAxisType
= "Lon";
>
> :History
= "GridDatatype extracted from
dataset
>
>
/eclipse1a/ftp/pub/radar/StIV/2006/01/01/hr/ST4.2006010100.06h";
>
> :Conventions =
"CF-1.0";
>
> :Originating_center
= "US National Weather Service
(NCEP)
subcenter
> =
4";
>
> :Generating_Process_or_Model
= "River Forecast Center
Quantitative
>
> Precipitation estimate
mosaic generated by
NCEP";
>
> :Product_Type =
"Accumulation";
>
> :cdm_data_type
= "Grid";
>
> :creator_name = "US National
Weather Service (NCEP) subcenter
=
4";
>
> :file_format =
"GRIB-1";
>
> :location
=
>
"/eclipse1a/ftp/pub/radar/StIV/2006/01/01/hr/ST4.2006010100.06h";
>
> :history = "Direct
read of GRIB into NetCDF-Java 2.2
API";
>
> :_CoordinateModelRunDate
= "2005-12-31T12:00:00Z";
>
>
=====================================================
>
> On 6/5/07, Steve Kopp <address@hidden <mailto:address@hidden>>
wrote:
>
>
>
>
> > Ben, the dataset
contains no projection information. Without
this, we
>
> > won't
know where else to draw anything.
>
>
>
>
> > Could you send us
a screen shot of what you are seeing?
>
>
>
>
>
> Thanks,
>
>
>
>
>
> Steve
>
>
>
>
>
>
>
> > -----Original
Message-----
>
> > From:
address@hidden <mailto:address@hidden>
[
> mailto:address@hidden] On Behalf
Of
>
> > Ben Domenico
>
> > Sent: Tuesday, June
05, 2007 11:32 AM
>
> > To:
Steve Kopp
>
> > Subject:
attached file
>
>
>
>
> > Hi Steve,
>
> >
>
>
> Don't know if this will work, but I'm attaching one of
the
CF-netCDF
>
> > files
I got from that NCDC radar data server. Let me know
whether
>
> > this comes through
OK.
>
>
>
>
> > --
Ben
>
>
>
>
>
>
>
>