Re: Lat/Lon Question

From: Greg Garrett - NOAA Federal <greg.garrett_at_nyahnyahspammersnyahnyah>
Date: Wed Jul 09 2014 - 14:11:14 MDT

Rick,

What I am really trying to do is extract a subset of data from a conus
native lambert conformal projected domain. The bounding box of my sub
domain is in lat/lon. Since lat/lon is not a grid in my grib2 file, I have
no way that I can figure out how to tell ncl to only pull information out
for my area of interest.

The grib2 file is the 3km HRRR model for the conus which is extremely
large. I am using the opendap version of ncl in an effort to only extract
parameter data for just my immediate area after opening the url of the
grib2 file.

 I have a ncl_filedump of one of the grib files below for reference. Any
ideas?

Greg

 Copyright (C) 1995-2014 - All Rights Reserved
 University Corporation for Atmospheric Research
 NCAR Command Language Version 6.2.0
 The use of this software is governed by a License Agreement.
 See http://www.ncl.ucar.edu/ for more details.

Variable: f
Type: file
filename: wrftwo_subh_RUN_2014-07-09T16:00:00Z
path:
http://esrl.noaa.gov/gsd/thredds/dodsC/hrrr/conus/wrftwo_subh/runs/wrftwo_subh_RUN_2014-07-09T16:00:00Z
   file global attributes:
      Originating_or_generating_Center : The NOAA Forecast Systems
Laboratory, Boulder, CO, USA
      Originating_or_generating_Subcenter : 0
      GRIB_table_version : 2,1
      Type_of_generating_process : Forecast

Analysis_or_forecast_generating_process_identifier_defined_by_originating_centre
: High-Resolution Rapid Refresh
      Conventions : CF-1.4, _Coordinates
      history : Read using CDM IOSP Grib2Collection ;
FMRC Run 2014-07-09T16:00:00Z Dataset
      featureType : GRID
      file_format : GRIB-2
      _CoordSysBuilder : ucar.nc2.dataset.conv.CF1Convention
      cdm_data_type : GRID
      location : Proto fmrc:wrftwo_subh
   dimensions:
      ncl_scalar = 1
      height_above_ground = 1
      height_above_ground1 = 1
      height_above_ground2 = 1
      height_above_ground3 = 1
      height_above_ground_layer = 1
      height_above_ground_layer1 = 1
      height_above_ground_layer1_bounds_1 = 2
      height_above_ground_layer_bounds_1 = 2
      time = 61
      x = 1799
      y = 1059
   variables:
      integer LambertConformal_Projection ( ncl_scalar )
         long_name :
         grid_mapping_name : lambert_conformal_conic
         latitude_of_projection_origin : 38.5
         longitude_of_central_meridian : 262.5
         standard_parallel : 38.5
         earth_radius : 6367470
         _CoordinateTransformType : Projection
         _CoordinateAxisTypes : GeoX GeoY

      float height_above_ground_layer_bounds ( height_above_ground_layer,
height_above_ground_layer_bounds_1 )
         units : m
         long_name : bounds for height_above_ground_layer

      float height_above_ground_layer1_bounds ( height_above_ground_layer1,
height_above_ground_layer1_bounds_1 )
         units : m
         long_name : bounds for height_above_ground_layer1

      double time_offset ( time )
         long_name : offset hour from start of run for coordinate = time
         standard_name : forecast_period
         units : hours since 2014-07-08T18:00:00Z
         missing_value : nan
         _FillValue : nan

      float x ( x )
         units : km
         long_name : projection_x_coordinate
         standard_name : projection_x_coordinate
         _CoordinateAxisType : GeoX

      float y ( y )
         units : km
         long_name : projection_y_coordinate
         standard_name : projection_y_coordinate
         _CoordinateAxisType : GeoY

      float height_above_ground ( height_above_ground )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      float height_above_ground1 ( height_above_ground1 )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      float height_above_ground_layer ( height_above_ground_layer )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         bounds : height_above_ground_layer_bounds
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      float height_above_ground_layer1 ( height_above_ground_layer1 )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         bounds : height_above_ground_layer1_bounds
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      float height_above_ground2 ( height_above_ground2 )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      float height_above_ground3 ( height_above_ground3 )
         units : m
         long_name : Specified height level above ground
         positive : up
         Grib2_level_type : 103
         datum : ground
         _CoordinateAxisType : Height
         _CoordinateZisPositive : up

      double time ( time )
         long_name : Forecast time for ForecastModelRunCollection
         standard_name : time
         units : hours since 2014-07-08T18:00:00Z
         missing_value : nan
         _CoordinateAxisType : Time
         _FillValue : nan

      float Temperature_height_above_ground ( time, height_above_ground, y,
x )
         units : K
         long_name : Temperature @ Specified height level above ground
         missing_value : nan
         description : Mean temperature in lowest 30 mb
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-0_L103
         Grib2_Parameter : ( 0, 0, 0 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Temperature
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground y x
         _FillValue : nan

      float Dew-point_temperature_height_above_ground ( time,
height_above_ground, y, x )
         units : K
         long_name : Dew-point temperature @ Specified height level above
ground
         missing_value : nan
         description : Mean dewpoint temperature in lowest 30 mb
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-6_L103
         Grib2_Parameter : ( 0, 0, 6 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Dew-point temperature
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground y x
         _FillValue : nan

      float Convective_Initiation1_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Initiation1 @ null
         missing_value : nan
         description : Time since last convective initation (> 1 hr) based
upon lightning threat 3 and no adjacent activity
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-195_L200
         Grib2_Parameter : ( 0, 0, 195 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Convective Initiation1
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Convective_Acitivity1_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Acitivity1 @ null
         missing_value : nan
         description : Time since last convective activity based upon
lightning threat 3
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-196_L200
         Grib2_Parameter : ( 0, 0, 196 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Convective Acitivity1
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Convective_Activitiy2_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Activitiy2 @ null
         missing_value : nan
         description : Time since last convective activity based upon
vertical flux of rain and graupel
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-201_L200
         Grib2_Parameter : ( 0, 0, 201 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Convective Activitiy2
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Convective_Activity3_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Activity3 @ null
         missing_value : nan
         description : Time since last convective activitiy based upon 35
dBZ reflectivity at -10C
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-0-202_L200
         Grib2_Parameter : ( 0, 0, 202 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Temperature
         Grib2_Parameter_Name : Convective Activity3
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Specific_humidity_height_above_ground ( time,
height_above_ground, y, x )
         units : kg/kg
         long_name : Specific humidity @ Specified height level above ground
         missing_value : nan
         description : Specific humidity at 2 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-0_L103
         Grib2_Parameter : ( 0, 1, 0 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Specific humidity
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground y x
         _FillValue : nan

      float Precipitation_rate_surface ( time, y, x )
         units : kg.m-2.s-1
         long_name : Precipitation rate @ Ground or water surface
         missing_value : nan
         description : Precipitation rate
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-7_L1
         Grib2_Parameter : ( 0, 1, 7 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Precipitation rate
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Precipitation_Type4_surface ( time, y, x )
         units : flag
         long_name : Precipitation Type4 @ Ground or water surface
         missing_value : nan
         description : Categorical rain (yes=1 no=0)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-192_L1
         Grib2_Parameter : ( 0, 1, 192 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Precipitation Type4
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Precipitation_Type3_surface ( time, y, x )
         units : flag
         long_name : Precipitation Type3 @ Ground or water surface
         missing_value : nan
         description : Categorical freezing rain (yes=1 no=0)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-193_L1
         Grib2_Parameter : ( 0, 1, 193 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Precipitation Type3
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Precipitation_Type2_surface ( time, y, x )
         units : flag
         long_name : Precipitation Type2 @ Ground or water surface
         missing_value : nan
         description : Categorical ice pellets (yes=1 no=0)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-194_L1
         Grib2_Parameter : ( 0, 1, 194 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Precipitation Type2
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Precipitation_Type1_surface ( time, y, x )
         units : flag
         long_name : Precipitation Type1 @ Ground or water surface
         missing_value : nan
         description : Categorical snow (yes=1 no=0)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-195_L1
         Grib2_Parameter : ( 0, 1, 195 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Precipitation Type1
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Convective_Initiation2_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Initiation2 @ null
         missing_value : nan
         description : Time since last convective initation (> 1 hr) based
upon flux of rain/graupel and no adjacent activity
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-213_L200
         Grib2_Parameter : ( 0, 1, 213 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Convective Initiation2
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Convective_Initiation3_Entire_atmosphere ( time, y, x )
         units : minutes
         long_name : Convective Initiation3 @ null
         missing_value : nan
         description : Time since last convective initation (> 1 hr) based
upon 35 dBZ reflectivity at -10C and no adjacent activity
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-1-214_L200
         Grib2_Parameter : ( 0, 1, 214 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Moisture
         Grib2_Parameter_Name : Convective Initiation3
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float u-component_of_wind_height_above_ground ( time,
height_above_ground3, y, x )
         units : m/s
         long_name : u-component of wind @ Specified height level above
ground
         missing_value : nan
         description : U-component of wind at 10 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-2-2_L103
         Grib2_Parameter : ( 0, 2, 2 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Momentum
         Grib2_Parameter_Name : u-component of wind
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground3 y x
         _FillValue : nan

      float v-component_of_wind_height_above_ground ( time,
height_above_ground3, y, x )
         units : m/s
         long_name : v-component of wind @ Specified height level above
ground
         missing_value : nan
         description : V-component of wind at 10 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-2-3_L103
         Grib2_Parameter : ( 0, 2, 3 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Momentum
         Grib2_Parameter_Name : v-component of wind
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground3 y x
         _FillValue : nan

      float Wind_mixing_energy_height_above_ground ( time,
height_above_ground2, y, x )
         units : J
         long_name : Wind mixing energy @ Specified height level above
ground
         missing_value : nan
         description : Wind energy generation potential using
0.5*density*speed^3 at 80 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-2-19_L103
         Grib2_Parameter : ( 0, 2, 19 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Momentum
         Grib2_Parameter_Name : Wind mixing energy
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground2 y x
         _FillValue : nan

      float Wind_speed_gust_surface ( time, y, x )
         units : m/s
         long_name : Wind speed (gust) @ Ground or water surface
         missing_value : nan
         description : Wind gust speed at 10 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-2-22_L1
         Grib2_Parameter : ( 0, 2, 22 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Momentum
         Grib2_Parameter_Name : Wind speed (gust)
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Pressure_surface ( time, y, x )
         units : Pa
         long_name : Pressure @ Ground or water surface
         missing_value : nan
         description : Surface pressure
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-0_L1
         Grib2_Parameter : ( 0, 3, 0 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : Pressure
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Geopotential_height_cloud_base ( time, y, x )
         units : gpm
         long_name : Geopotential height @ Cloud base level
         missing_value : nan
         description : Adiabatic condensation level above ground (LCL)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-5_L2
         Grib2_Parameter : ( 0, 3, 5 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : Geopotential height
         Grib2_Level_Type : 2
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Geopotential_height_cloud_tops ( time, y, x )
         units : gpm
         long_name : Geopotential height @ Level of cloud tops
         missing_value : nan
         description : Adiabatic condensation level above ground (LCL)
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-5_L3
         Grib2_Parameter : ( 0, 3, 5 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : Geopotential height
         Grib2_Level_Type : 3
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Echo_Top_cloud_tops ( time, y, x )
         units : m
         long_name : Echo Top @ Level of cloud tops
         missing_value : nan
         description : Echo top height of 18dBZ surface
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-193_L3
         Grib2_Parameter : ( 0, 3, 193 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : Echo Top
         Grib2_Level_Type : 3
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float VIL_Entire_atmosphere ( time, y, x )
         units : kg/m2
         long_name : VIL @ null
         missing_value : nan
         description : Vertically integrated liquid
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-194_L200
         Grib2_Parameter : ( 0, 3, 194 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : VIL
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Radar_VIL_Entire_atmosphere ( time, y, x )
         units : kg/m2
         long_name : Radar VIL @ null
         missing_value : nan
         description : Radar-derived vertically integrated liquid
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-3-195_L200
         Grib2_Parameter : ( 0, 3, 195 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Mass
         Grib2_Parameter_Name : Radar VIL
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Radiation_surface ( time, y, x )
         units : W/m2
         long_name : Radiation @ Ground or water surface
         missing_value : nan
         description : Incoming shortwave radiation at the surface
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-4-192_L1
         Grib2_Parameter : ( 0, 4, 192 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Short-wave radiation
         Grib2_Parameter_Name : Radiation
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Radiation_atmosphere_top ( time, y, x )
         units : W/m2
         long_name : Radiation @ Nominal top of the atmosphere
         missing_value : nan
         description : Outgoing longwave radiation at top of atmosphere
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-5-193_L8
         Grib2_Parameter : ( 0, 5, 193 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Long-wave radiation
         Grib2_Parameter_Name : Radiation
         Grib2_Level_Type : 8
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Updraft_Helicity_height_above_ground_layer ( time,
height_above_ground_layer, y, x )
         units : m2/s2
         long_name : Updraft Helicity @ Specified height level above ground
layer
         missing_value : nan
         description : Updraft helicity in layer 2-5 km above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-7-197_L103_layer
         Grib2_Parameter : ( 0, 7, 197 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Thermodynamic stability indices
         Grib2_Parameter_Name : Updraft Helicity
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground_layer y x
         _FillValue : nan

      float Reflectivity_height_above_ground ( time, height_above_ground1,
y, x )
         units : dBZ
         long_name : Reflectivity @ Specified height level above ground
         missing_value : nan
         description : Reflectivity at 1 km above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-16-195_L103
         Grib2_Parameter : ( 0, 16, 195 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Forecast radar imagery
         Grib2_Parameter_Name : Reflectivity
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground1 y x
         _FillValue : nan

      float Composite_Reflectivity_Entire_atmosphere ( time, y, x )
         units : dBZ
         long_name : Composite Reflectivity @ null
         missing_value : nan
         description : Maximum reflectivity in model column
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-16-196_L200
         Grib2_Parameter : ( 0, 16, 196 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Forecast radar imagery
         Grib2_Parameter_Name : Composite Reflectivity
         Grib2_Level_Type : 200
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float Visibility_surface ( time, y, x )
         units : m
         long_name : Visibility @ Ground or water surface
         missing_value : nan
         description : Surface visibility
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_0-19-0_L1
         Grib2_Parameter : ( 0, 19, 0 )
         Grib2_Parameter_Discipline : Meteorological products
         Grib2_Parameter_Category : Physical atmospheric properties
         Grib2_Parameter_Name : Visibility
         Grib2_Level_Type : 1
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time y x
         _FillValue : nan

      float SBT123_height_above_ground_layer ( time,
height_above_ground_layer1, y, x )
         units : m2/s2
         long_name : SBT123 @ Specified height level above ground layer
         missing_value : nan
         description : Updraft helicity in layer 1-6 km above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_3-192-1_L103_layer
         Grib2_Parameter : ( 3, 192, 1 )
         Grib2_Parameter_Discipline : Space products
         Grib2_Parameter_Name : SBT123
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground_layer1 y x
         _FillValue : nan

      float u-component_of_current_height_above_ground ( time,
height_above_ground2, y, x )
         units : m/s
         long_name : u-component of current @ Specified height level above
ground
         missing_value : nan
         description : U-component of wind at 80 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_10-1-2_L103
         Grib2_Parameter : ( 10, 1, 2 )
         Grib2_Parameter_Discipline : Oceanographic products
         Grib2_Parameter_Category : Currents
         Grib2_Parameter_Name : u-component of current
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground2 y x
         _FillValue : nan

      float v-component_of_current_height_above_ground ( time,
height_above_ground2, y, x )
         units : m/s
         long_name : v-component of current @ Specified height level above
ground
         missing_value : nan
         description : V-component of wind at 80 m above ground level
         grid_mapping : LambertConformal_Projection
         Grib_Variable_Id : VAR_10-1-3_L103
         Grib2_Parameter : ( 10, 1, 3 )
         Grib2_Parameter_Discipline : Oceanographic products
         Grib2_Parameter_Category : Currents
         Grib2_Parameter_Name : v-component of current
         Grib2_Level_Type : 103
         Grib2_Generating_Process_Type : Forecast
         coordinates : time_run time height_above_ground2 y x
         _FillValue : nan






On Wed, Jul 9, 2014 at 12:03 PM, Rick Brownrigg <brownrig@ucar.edu> wrote:

> Hi Greg,
>
> I'm not aware of a means to do this from within NCL. If I had to do it,
> I'd use the Proj4 cartographic projection library, which would entail:
>
> - writing the X/Ys to a temp file,
> - issue a system() call with a proper command-line containing the L.C.
> projection details to the "proj" command, which would then read the temp
> file and write a new file containing lat/lons
> - read the lat/lon
>
> Its a bit clunky, but not too hard *if* you already have Proj4 and are
> familiar with it (http://trac.osgeo.org/proj/)
>
> Hope that helps...
> Rick
>
>
>
> On Wed, Jul 9, 2014 at 9:51 AM, Greg Garrett - NOAA Federal <
> greg.garrett@noaa.gov> wrote:
>
>> I am working with a Lambert Conformal projected dataset with GeoX and
>> GeoY x and y coordinates (excerpt below). There are no latitude or
>> longitude coordinates.
>> Can anyone tell me if it is possible to compute lat/lon from the x,y, and
>> projection information and if so, how?
>>
>> Thanks,
>>
>> Greg
>>
>>
>> x = 1799
>> y = 1059
>> variables:
>> integer LambertConformal_Projection ( ncl_scalar )
>> long_name :
>> grid_mapping_name : lambert_conformal_conic
>> latitude_of_projection_origin : 38.5
>> longitude_of_central_meridian : 262.5
>> standard_parallel : 38.5
>> earth_radius : 6367470
>> _CoordinateTransformType : Projection
>> _CoordinateAxisTypes : GeoX GeoY
>>
>> float x ( x )
>> units : km
>> long_name : projection_x_coordinate
>> standard_name : projection_x_coordinate
>> _CoordinateAxisType : GeoX
>>
>> float y ( y )
>> units : km
>> long_name : projection_y_coordinate
>> standard_name : projection_y_coordinate
>> _CoordinateAxisType : GeoY
>>
>> _______________________________________________
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>>
>>
>

Received on Wed Jul 09 08:11:42 2014

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