Re: interpolate pixel level data into regular grid

I have tried this and still there is error. The message is:
write_grid_description: can't determine what type of source grid you have.
I think this is related to lat/lon of var I want to interpolate. Following is the script I have tried. Please guide me what's wrong of my script. Thanks!

CL

---------------------------
begin

;---Interpolation methods to use
    methods = (/"bilinear","patch","conserve"/)
    nmethods = dimsizes(methods)

;---Read variable to regrid

    srcFileName = "../dat/biomass_burning_20120313_18_23.nc"
    sfile = addfile(srcFileName,"r") ; source grid

    x = sfile->CO_emission ; 6 x 1129
    var = x(:,0) ; first time
    latin = sfile->Latitude
    latin@units = "degrees_north"
    lonin = sfile->Longitude
    lonin@units = "degrees_east"

    dimx = dimsizes( var )
    nlat = dimx(0)
    mlon = dimx(0)

    print(nlat)
    print(mlon)

;---Create destination lat/lon arrays
    NLAT36 = 112
    MLON36 = 148

; lat36 = new (/NLAT36,MLON36/)
; lon36 = new (/NLAT36,MLON36/)

    lat36 = asciiread("/data11/cluo/cmaq4.6/data/post/obs/grids_148x112/crogrids_lat_148x112.dat" \
                       , (/NLAT36,MLON36/),"float")
    lon36 = asciiread("/data11/cluo/cmaq4.6/data/post/obs/grids_148x112/crogrids_lon_148x112.dat" \
                       , (/NLAT36,MLON36/),"float")

    Opt = True ; Regridding options
    Opt@ForceOverwrite = True
    Opt@DstGridLat = lat36
    Opt@DstGridLon = lon36

    var_regrid = ESMF_regrid(var,Opt)

-----------------------

----- Original Message -----
From: "Mary Haley" <haley@ucar.edu>
To: "Chao Luo" <chao.luo@eas.gatech.edu>
Cc: "ncl-talk Talk" <ncl-talk@ucar.edu>
Sent: Tuesday, October 30, 2012 10:50:05 AM
Subject: Re: interpolate pixel level data into regular grid

Chao,

Dennis suggested the ESMF regridding routines.

You might want to look at ESMF_regrid specifically.

Since you have 1D coordinate arrays for the source grid, and want a 12 km x 12 km destination grid, I suggest looking at example ESMF_regrid_2.ncl:

http://www.ncl.ucar.edu/Applications/ESMF.shtml

This shows how to regrid from a rectilinear grid (which it looks like you have), to a lat/lon grid that you define, which I assume you have.

This example uses all three methods of interpolation (bilinear, patch, conserve) and regrids to two different grids.

I think you just need to set:

---Common resources
    Opt = True

    Opt@ForceOverwrite = True

    Opt@DstGridLat = lat12
    Opt@DstGridLon = lon12

where lat12 and lon12 contain arrays that represent the 12 km grid.

Then, call ESMF_regrid:

  var_regrid = ESMF_regrid(var,Opt)

Where "var" is the variable you want to regrid that contains the 1D coordinate arrays.

--Mary

On Oct 30, 2012, at 11:09 AM, Luo, Chao wrote:

> x refer to time. This is hourly biomass emission data from 18:00-23:00 on 3/17/2012. What I want to do is to interpolate this pixel level data to regular grid (12km x 12km), but don't know which function can be used. Any suggestions are very appreciated!
>
> ----- Original Message -----
> From: "Dennis Shea" <shea@ucar.edu>
> To: "Chao Luo" <chao.luo@eas.gatech.edu>
> Cc: "ncl-talk" <ncl-talk@ucar.edu>
> Sent: Monday, October 29, 2012 5:00:34 PM
> Subject: Re: interpolate pixel level data into regular grid
>
> The issue is "What does the named dimension 'x' refer to?"
> There is nothing on the file to indicate its purpose.
> You must find out before proceding.
>
> Attached is a simple NCL script that plots the data.
>
> netcdf biomass_burning_20120317_18_23 {
> dimensions:
> x = 6 ;
> y = 371 ;
> variables:
> float Latitude(y) ;
> Latitude:long_name = "Latitude" ;
> Latitude:units = "degree" ;
> Latitude:valid_range = -90.f, 90.f ;
> Latitude:scale_factor = 1.f ;
> Latitude:add_offset = 0.f ;
> Latitude:_FillValue = -9.f ;
> float Longitude(y) ;
> Longitude:long_name = "Longitude" ;
> Longitude:units = "degree" ;
> Longitude:valid_range = -180.f, 180.f ;
> Longitude:scale_factor = 1.f ;
> Longitude:add_offset = 0.f ;
> Longitude:_FillValue = -9.f ;
> float Burned_area(y, x) ;
> [snip]
>
> On 10/29/12 5:15 PM, Luo, Chao wrote:
>> Hi Dennis,
>>
>> I have checked example 8 and 15. They both require two dimensional lat/lon. The lat/lon of files I have are 1 dimension, but data array is 2D (I am not familiar with these format data). Do I need convert lat/lon from 1D to 2D, and then do interpolation in this case? I am attaching the file. Any suggestions and help are very appreciated!
>>
>> CL
>>
>> ----- Original Message -----
>> From: "Dennis Shea" <shea@ucar.edu>
>> To: "Chao Luo" <chao.luo@eas.gatech.edu>
>> Cc: "ncl-talk" <ncl-talk@ucar.edu>
>> Sent: Monday, October 29, 2012 3:35:54 PM
>> Subject: Re: interpolate pixel level data into regular grid
>>
>> http://www.ncl.ucar.edu/Applications/ESMF.shtml
>>
>> Examples 8 and 15 may be of use.
>>
>> On 10/29/12 3:59 PM, Luo, Chao wrote:
>>> Hi,
>>>
>>> I was wondering if NCL has some functions, which can be used to
>>> interpolate satellite pixel level data into regular data. Any helps are
>>> very appreciated.
>>>
>>> CL
>>>
>>>
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Received on Tue Oct 30 14:07:05 2012