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

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 11:44:19 2012