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

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 16:41:50 2012