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

Thanks for your help, we will study, I'll be consulting anything.

 Thanks
 Gualberto

> Date: Tue, 7 Aug 2012 16:01:48 -0600
> Subject: Re: FW: 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
>
> Gualberto,
>
> Here is some untested code to make a list of the Y/X cordinate pairs.
> Since you are new to NCL, I suggest that you study this line by line
> to see how it works, then try to fix any problems that might come up.
> Good luck.
>
> By the way, I can not remember whether the Geotrans software needs
> coordinate pairs in Y/X or X/Y order. Please check the Geotrans
> documentation, or experiment both ways, and change the sprintf
> statement accordingly.
>
> begin
> infile = "MMOUT_DOMAIN1.nc"
> outfile = "y-x-coordinates.txt"
>
> print ("Read input file coordinates: " + infile)
> f = addfile (infile, "r")
> nx = dimsizes (f->lon)
> ny = dimsizes (f->lat)
>
> print ("nx = " + nx)
> print ("ny = " + ny)
>
> lines = new (nx*ny, string)
> j = 0
>
> do y = 0, ny-1
> do x = 0, nx-1
> lines(j) = sprintf ("%12.5f", f->lat(y)) + sprintf ("%12.5f", f->lon(x))
> j = j + 1
> end do
> end do
>
> print ("Write text file: " + outfile)
> asciiwrite (outfile, lines)
> end
>
> --Dave
>
> On Tue, Aug 7, 2012 at 2:06 PM, Gualberto Hernández Juárez
> <betoic@hotmail.com> 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 16:12:54 2012