From: Debasish <debasish_at_nyahnyahspammersnyahnyah>

Date: Tue Feb 08 2011 - 09:46:19 MST

Date: Tue Feb 08 2011 - 09:46:19 MST

Dear Dennis

Thanks for your response.

*> I am not clear what you mean by
*

*> "interpolate 2d randomly-spaced data to
*

*> another 2d randomly-spaced data or 2d randomly
*

*> spaced data to directly RCMs grid"
*

*>
*

My primary aim is to interpolate 2d random spaced data to RCM grid

For example, I have 2d random spaced data x(npts) with lat(npts) and lon(npts). I would like to interpolate the data to RCM grid i.e. lat2d(m,n) and lon2d(m,n) and interpolated output should be xint(m,n)

I believe there is two ways to solve this

[1]

direct interpolation of 2d random spaced data on to RCM grid

[2]

First interpolate 2d random spaced data to another 2d random spaced data and then convert new random space data to RCM grid

Assume, function points2points(X[*],Y[*],z[*].X1[*],Y1[*],opts:logical)

step1: lat1d = ndtooned(lat2d)

lon1d = ndtooned(lon2d)

step2: xint1d = points2points(lon(npts),lat(npts),x(npts),lon1d(m x n), lat1d(m x n), opts)

step3: xint = onedtond(xint1d, (/yc,x/))

*> ---
*

*>
*

*> There is a function in NCL' contributed.ncl that may work.
*

*> Like "natgrid" this can be slow!!!!
*

*>
*

*> function obj_anal_ic_deprecated(X[*],Y[*],Z[*],lon:numeric,lat:numeric \
*

*> ,dcrit[*]:numeric, opt:logical)
*

*>
*

*> ===
*

*> opt = 0
*

*> zrcm = obj_anal_ic_deprecated(loni,lati,zi, dcrit, lon2d,lat2d, opt)
*

*>
*

*> input: loni[*], lati[*], zi[*]
*

*>
*

*> output: lon2d[*][*], lat2d[*][*]
*

*>
*

*> ; dcrit - 1D array containing successive radii of influence.
*

*> ; Must be expressed in degrees latitude and should be
*

*> ; monotonically de. eg: dcrit = (/5, 3/)
*

*>
*

I believe that function "obj_anal_ic_deprecated" will works for me however I have few questions regarding the function.

[1]

Do you know which version the function is created? because when I try to use it according to the webpage example (http://www.ncl.ucar.edu/Document/Functions/Contributed/obj_anal_ic_deprecated.shtml) it does not recognized the function:

fatal:Undefined identifier: (obj_anal_ic_deprecated) is undefined, can't continue

I already load the "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl" and I am using NCL version 5.1.1

[2]

I would like to clarify that in webpage of the function output lat, lon is 1dimensional so I need to follow the method [2] (mentioned above) or can I use 2dimension lat (lat2d) and lon(lon2d) too (method[1]). If like to use lat2d(m,n) and lon2d(m,n) and corresponding output(m,n), what are the modifications?

[3]

rscan (in webpage) or dcrit (in your script) can be one dimensional array of any length or is there any particular reason to choose length 2

or length 3 with respect to the accuracy

Thank again for your help

Debasish

On 2/7/11 9:59 AM, Debasish wrote:

*>
*

*>> Hello,
*

*>>
*

*>> Thanks Dennis for your suggestion. However I believe the function "triple2grid2d" places randomly-spaced data onto the nearest locations of a grid instead of interpolation while I need to do a interpolation. I also checked http://www.ncl.ucar.edu/Document/Functions/regrid.shtml but did not find any function that can interpolate randomly-spaced data to another randomly-spaced data or RCMs grid.
*

*>>
*

*>> Therefore, I would like to know is there any function or any way in NCL to interpolate 2d randomly-spaced data to another 2d randomly-spaced data or 2d randomly spaced data to directly RCMs grid.
*

*>>
*

*>> Any help in this regard will be appreciated and sorry for any inconvenience
*

*>>
*

*>> Thanks
*

*>>
*

*>> Debasish
*

*>>
*

*>>
*

*>>
*

*>>
*

*>> On 2011-02-03, at 14:36, Dennis Shea wrote:
*

*>>
*

*>>> NCL does not read Excel spradsheeys.
*

*>>> You would have to convert to ascii, the use asciiread.
*

*>>>
*

*>>> "natvar" is high quality but is known to be slow.
*

*>>>
*

*>>> Really, if you have a large number of high res\
*

*>>> grids you need interpolated to an RCM grid,
*

*>>> there is not magic bullet. it will take time.
*

*>>>
*

*>>> The following *may* be useful.
*

*>>>
*

*>>>
*

*>>> http://www.ncl.ucar.edu/Document/Functions/Built-in/triple2grid2d.shtml
*

*>>>
*

*>>> Good luck
*

*>>>
*

*>>> On 2/3/11 12:02 PM, Debasish wrote:
*

*>>>> Dear NCL Users
*

*>>>>
*

*>>>> I guess I am getting missing outputs because of the assumption that xin
*

*>>>> is gridded RCM data because neither lon proceeds left to right nor lat
*

*>>>> proceeds from south-to-north.
*

*>>>>
*

*>>>> I have tried to use "natgrid" assuming xi (mxn) with lat(mxn) and
*

*>>>> lon(mxn) but the program is hang. I guess it does not work too.
*

*>>>>
*

*>>>> Therefore, I would like to know how do I interpolate this data (high
*

*>>>> resolution data) to RCM grid with lat2d(172,180), lon2d(172,180).
*

*>>>> Meanwhile I counted that there are nearly 450 RCM grid over the input
*

*>>>> domain; so I would like to interpolate the input data to this 450 CRCM
*

*>>>> grid.
*

*>>>> I am sending the part (total file has 17536 lat, lon and xin) of lat and
*

*>>>> lon of the input data for your convenience .
*

*>>>>
*

*>>>> Any help in this regard will be appreciated
*

*>>>>
*

*>>>> Thanks
*

*>>>>
*

*>>>> Debasish
*

*>>>>
*

*>>>> =
*

*>>>>
*

*>>>>
*

*>>>>
*

*>>>> Begin forwarded message:
*

*>>>>
*

*>>>>> *From: *Debasish<debasish@sca.uqam.ca<mailto:debasish@sca.uqam.ca>>
*

*>>>>> *Date: *1 février 2011 16:42:48 HNE
*

*>>>>> *To: *Ncl Talk<ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>>
*

*>>>>> *Subject: **[ncl-talk] interpolation gridded data to rcm*
*

*>>>>>
*

*>>>>> Dear NCL users,
*

*>>>>>
*

*>>>>> I have gridded data xin (m,n) with lat(m,n) and lon(m,n) for smaller
*

*>>>>> domain. I would like to interpolate the data to RCM grid lat2d(a,b)
*

*>>>>> and lon2d(a,b) for bigger domian.
*

*>>>>> I follow the followings steps:
*

*>>>>>
*

*>>>>> 1. I assume "xin" as RCM gridded data
*

*>>>>> 2. convert lat2d and lon2d to 1d array lat1d and lon1d
*

*>>>>> 3. Use "rcm2points" function
*

*>>>>> xout1d = rcm2points(lat,lon,xin,lat1d,lon1d,0)
*

*>>>>> 4. then convert xout1d to 2d
*

*>>>>> but all the values of xout1d are missing
*

*>>>>>
*

*>>>>> Any suggestion to fix these problem will be appreciated
*

*>>>>>
*

*>>>>> Thanks
*

*>>>>>
*

*>>>>> Debasish
*

*>>>>> _______________________________________________
*

*>>>>> ncl-talk mailing list
*

*>>>>> List instructions, subscriber options, unsubscribe:
*

*>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
*

*>>>>
*

*>>>> =
*

*>>>>
*

*>>>>
*

*>>>>
*

*>>>> _______________________________________________
*

*>>>> ncl-talk mailing list
*

*>>>> List instructions, subscriber options, unsubscribe:
*

*>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
*

*>>
*

*>> _______________________________________________
*

*>> ncl-talk mailing list
*

*>> List instructions, subscriber options, unsubscribe:
*

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*

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Received on Tue Feb 8 10:31:43 2011

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