Re: FW: I mean regridding the data to a rectiliniear lat / lon grid

From: Gualberto Hernández Juárez <betoic_at_nyahnyahspammersnyahnyah>
Date: Tue Aug 07 2012 - 20:20:09 MDT

 Dave, I send the image From: dbrown@ucar.edu
Subject: Re: FW: I mean regridding the data to a rectiliniear lat / lon grid
Date: Tue, 7 Aug 2012 18:16:24 -0600
To: betoic@hotmail.com

Sorry maybe I misunderstand. I have the NetCDF file MMOUT_DOMAIN1.nc. But I thought you said you uploaded an image (picture ??) of the plot you made in ArcMap. I would like to see the picture if you can send it. -dave
On Aug 7, 2012, at 5:23 PM, Gualberto Hernández Juárez wrote:This is the file MMOUT_DOMAIN1.nc
 
The file you put in place it ftp://ftp.cgd.ucar.edu/incoming/

 
From: dbrown@ucar.edu
Subject: Re: FW: I mean regridding the data to a rectiliniear lat / lon grid
Date: Tue, 7 Aug 2012 17:19:16 -0600
To: betoic@hotmail.com

(offline)I need to know what you called the file in order to retrieve it. -dave
On Aug 7, 2012, at 5:10 PM, Gualberto Hernández Juárez wrote:Thanks for your reply Dave,

I plot the file only in ArcMap of ArcGIS, place an image in the directory:

 
ftp://ftp.cgd.ucar.edu/incoming/
 
 
I just have to put the map of the Mexican republic.

 
Subject: Re: FW: I mean regridding the data to a rectiliniear lat / lon grid
From: dbrown@ucar.edu
Date: Tue, 7 Aug 2012 16:41:41 -0600
CC: ncl-talk@ucar.edu
To: betoic@hotmail.com

Hi Gaulberto,Here is a way to write the text file as X/Y pairs as Dave Allured suggested:
  f = addfile ("MMOUT_DOMAIN1.nc", "r") x = f->lon y = f->lat nx = dimsizes(x) ny = dimsizes(y) x2d = conform_dims((/ny,nx/),x,1) y2d = conform_dims((/ny,nx/),y,0) outstr = sprintf("%9.3f",x2d) + " " + sprintf("%9.3f",y2d) asciiwrite("xy.txt",outstr)
I wonder if you have a plot of this grid in its native (Lambert Conformal) configuration. I have tried to plot it based on the LC parameters given in the data file, but so far I have been unsuccessful.A correct plot of the domain would help.
If you can get NCL to plot the data correctly in its native projection, then it is possible to compute the lat/lon coordinates using NCL by itself. -dave

On Aug 7, 2012, at 2:06 PM, Gualberto Hernández Juárez wrote:Dave,
How to make the text file, which you mention in the first point.

Thanks
Gualberto

> Date: Tue, 7 Aug 2012 11:44:09 -0600
> Subject: Re: I mean regridding the data to a rectiliniear lat / lon grid
> From: dave.allured@noaa.gov
> To: betoic@hotmail.com
> CC: ncl-talk@ucar.edu
>
> Here is one way. I am sure there are others.
>
> 1. Use NCL to make a text file containing a 1-dimensional ordered
> list of all X/Y coordinate pairs.
>
> 2. Use MPS Geotrans in batch mode to translate the list of
> coordinates from Lambert Conformal to terrestrial lat/lon. It's free
> software, and it supports a huge variety of known terrestrial
> coordinate systems.
>
> http://earth-info.nga.mil/GandG/geotrans/
>
> 3. Use NCL to read in the translated coordinates, and reshape them
> into 2-D lat and lon coordinate arrays.
>
> 4. Use one of the many NCL regridding functions, plus the 2-D
> coordinates from step 3, to regrid the data array to a rectilinear
> grid of your choice.
>
> This is an overview. Steps 1 and 3 are fairly straightforward NCL
> coding. Steps 2 and 4 will involve significant study to get them
> working correctly. HTH.
>
> --Dave
>
> On Tue, Aug 7, 2012 at 10:54 AM, Gualberto Hernández Juárez
> <betoic@hotmail.com> wrote:
> > I need *regrid* the 2D lat/lon to a rectilinear lat lon.
> >
> > any comments will be grateful enough support, I'm new to NCL.
> >
> > Thank you,
> > Gualberto
> >
> >
> >> Date: Tue, 7 Aug 2012 10:41:42 -0600
> >> From: shea@ucar.edu
> >> To: betoic@hotmail.com
> >> CC: ncl-talk@ucar.edu
> >> Subject: Re: I mean regridding the data to a rectiliniear lat /
> >> lon grid
> >>
> >> Technically, this is already a rectilinear grid.
> >>
> >> double lat ( lat )
> >> _CoordinateAxisType : GeoY
> >> axis : Y
> >> grid_spacing : 27.0 km
> >> long_name : y coordinate of projection
> >> standard_name : projection_y_coordinate
> >> units : km
> >>
> >> double lon ( lon )
> >> _CoordinateAxisType : GeoX
> >> axis : X
> >> grid_spacing : 27.0 km
> >> long_name : x coordinate of projection
> >> standard_name : projection_x_coordinate
> >> units : km
> >>
> >> float u10 ( time, lat, lon )
> >> long_name : 10 m u wind (m/sec)
> >> _FillValue : -9999
> >> grid_mapping : Lambert_Conformal
> >>
> >> The issue is that the poorly named 'lat' and 'lon' variables
> >> should be (say) 'y' and 'x'.
> >>
> >> Basically, the projection information
> >>
> >> character Lambert_Conformal ( ncl_scalar )
> >> grid_mapping_name : lambert_conformal_conic
> >> long_name :
> >> latitude_of_projection_origin : 0
> >> longitude_of_central_meridian : -124.17
> >> false_easting : 0
> >> false_northing : -27
> >> standard_parallel : 0
> >> _CoordinateTransformType : Projection
> >> _CoordinateAxisTypes : GeoX GeoY
> >> earth_shape : Earth spherical with radius of 6,371,229.0 m
> >> earth_radius : 6371229
> >>
> >> must be used to generate two-dimensional latitude and longitude
> >> coordinates for each grid point. Then the data can be plotted on the
> >> lambert map projection. Is this what you want?
> >>
> >> *** I have no idea how to do this. Maybe someone else does. ***
> >>
> >> Then, if you really want to *regrid* the 2D lat/lon to a rectilinear
> >> lat lon, you would have to use the ESMF regridding
> >> http://www.ncl.ucar.edu/Applications/ESMF.shtml
> >>
> >>
> >> On 8/7/12 10:12 AM, Gualberto Hernández Juárez wrote:
> >> > Hi,
> >> >
> >> > I mean regridding the data to a rectiliniear lat / lon grid
> >> >
> >> > locate the file in the directory:
> >> >
> >> > ftp://ftp.cgd.ucar.edu/incoming/
> >> >
> >> > or you can download from this link:
> >> >
> >> > https://dl.dropbox.com/u/96409134/MMOUT_DOMAIN1.nc
> >> >
> >> > Thanks I'll be awaiting your response.
> >> > Gualberto
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Received on Tue Aug 7 20:20:28 2012

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