[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: attached file



Hi Ben,

 

Yes we are trying to fix it in 9.3.

 

Thanks,

 

Noman

 


From: address@hidden [mailto:address@hidden] On Behalf Of Ben Domenico
Sent: Thursday, October 18, 2007 11:53 AM
To: Nawajish Noman
Cc: John Caron; address@hidden
Subject: Re: attached file

 

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
>
>     >
>
>     >
>
>