[ncl-talk] grid_area_avg
Kunal Bali
kunal.bali9 at gmail.com
Wed Oct 18 00:23:28 MDT 2017
printVarSummary(aot_subset), shows that aot_subset is undefined, which I am
unable to fix this problem yet.
If I used aot_subset(ilt1:ilt2,iln1:iln2) *=*
data(ilt1:ilt2,iln1:iln2) *instead
of *aot_subset(ilt1:ilt2,iln1:iln2) *:= *data(ilt1:ilt2,iln1:iln2)
then the error appeared as
*fatal:["Execute.c":7950]:Number of subscripts on right-hand-side do not
match number of dimensions of variable: (2), Subscripts used:
(3)*
basically, the data summary is
Variable: fnames
Type: string
Total Size: 8 bytes
1 values
Number of Dimensions: 1
Dimensions and sizes: [1]
Coordinates:
(0) ./maiactaotE.h00v03.20000550525-20003660700.nc
Variable: data
Type: float
Total Size: 2545920000 bytes
636480000 values
Number of Dimensions: 3
Dimensions and sizes: *[time | 442] x [YDim_grid1km | 1200] x
[XDim_grid1km | 1200]*
Coordinates:
time: [1301.416666666686..8767]
Number Of Attributes: 8
coordinates : GridLat_grid1km, GridLon_grid1km
hdfeos_name : Optical_Depth_055
projection : Albers Conical Equal_Area
unit : None
long_name : AOT at 0.55 micron
_FillValue_original : -28672
_FillValue : -28672
valid_range : ( -0.1, 5 )
(0) latitude (degrees_north) : min=11.2940312768897
max=24.54921980985786
(0) longitude (degrees_east) : min=68.08003670367275
max=81.63171349927691
*fatal:["Execute.c":7776]:aot_subset is undefined, can not subscript an
undefined variablefatal:["Execute.c":8640]:Execute: Error occurred at or
near line 38 in file test_extract.ncl*
*38 line is *
*aot_subset(ilt1:ilt2,iln1:iln2) = data(ilt1:ilt2,iln1:iln2)*
*fatal:Variable (aot_subset) is undefined*
regards
Kunal Bali
On Tue, Oct 17, 2017 at 3:05 PM, Guido Cioni <guidocioni at gmail.com> wrote:
> Why did you comment this line ?
>
> ;printVarSummary(aot_subset)
>
>
> That would have helped you in debugging the error on your own.
>
> You are using the re-assignment operator ":=". This means that every time
> you make an assignment the variable is created again. Thus, you cannot make
> this assignment
>
> * aot_subset(ilt1:ilt2,iln1:iln2) := data(ilt1:ilt2, iln1:iln2)*
>
>
> as NCL has no way to know the shape of aot_subset beforehand.
>
> The following should be used instead (notice the assignment with "=" in
> the second line).
>
> aot_subset := data
> aot_subset = aot_subset at _FillValue
> aot_subset(ilt1:ilt2,iln1:iln2) *=* data(ilt1:ilt2, iln1:iln2)
>
> Notice that this will (1) create an array which is shaped like data (2)
> fill it with fill values as you only want to compute the average over the
> subset (3) populate the array only in the lat-lon box provided. However I
> don't see why you would want to use such a complicated syntax when the
> following code would produce the same result
>
> aot_subset_avg=avg(data(ilt1:ilt2, iln1:iln2))
>
> If you have the right coordinate attributes you can even jump the first 7
> lines and do
>
> aot_subset_avg=avg(data({18:24},{74:78})
>
> but I don't know your data.
>
> As it was already suggested by Mary and others, PLEASE take time to debug
> the errors on your own.
>
> Regards,
>
> On 17. Oct 2017, at 11:25, Kunal Bali <kunal.bali9 at gmail.com> wrote:
>
>
> I did the following changes but still getting an error of *aot_subset*
> which is undefined.
> please let me know that how to fix or defined the *aot_subset *this
> problem.
>
>
>
> latv = (/ 18, 24/) ; for extracting grid box data
> lonv = (/ 74, 78 /)
> nm = getind_latlon2d (lat2d, lon2d, latv, lonv)
> ilt1 = nm(0,0) ; start lat index
> ilt2 = nm(1,0) ; start lon index
> iln1 = nm(0,1) ; end lat index
> iln2 = nm(1,1) ; end lon index
> lat_subset := lat2d(ilt1:ilt2,iln1:iln2)
> lon_subset := lon2d(ilt1:ilt2,iln1:iln2)
> aot_subset := data
> * aot_subset(ilt1:ilt2,iln1:iln2) := data(ilt1:ilt2, iln1:iln2)*
>
> ;printVarSummary(aot_subset)
> aot_avg = avg(data)
> aot_subset_avg = avg(*aot_subset*)
>
> ;print(nm)
> print("-----")
>
> do k=0,dimsizes(latv)-1
> n = nm(k,0)
> m = nm(k,1)
> print(lat2d(n,m)+" "+lon2d(n,m))
> print(" "+data(:,n,m)) ; nearest grid point at
> all time steps
> print("-----")
> end do
>
>
>
>
> regards
> Kunal Bali
>
>
>
>
>
>
> On Tue, Oct 17, 2017 at 12:41 PM, Kunal Bali <kunal.bali9 at gmail.com>
> wrote:
>
>> I have sent the ncl script and data to the incoming dir with the given
>> names as
>>
>> data = maiactaotE.h00v03.20003660525-20003660700.nc.bz2
>> ncl_script = extract_iiserb.ncl
>>
>> I am not able to define the var_subset in the given script.
>> please let me know if you have received the data and script?
>>
>>
>>
>>
>>
>> Kunal Bali
>>
>>
>>
>>
>>
>>
>> On Mon, Oct 16, 2017 at 11:07 PM, Mary Haley <haley at ucar.edu> wrote:
>>
>>> Kunal,
>>>
>>> You must make an effort to debug some of these problems on your own. The
>>> error is telling you that something is wrong around line 34 and it is
>>> telling you exactly what the problem is. Please try to fix this error.
>>>
>>> If you continue to have problems after fixing this error, then I need to
>>> ask you to provide the full script and data via ftp:
>>>
>>> http://www.ncl.ucar.edu/ftp_files.shtml
>>>
>>> However, make sure you debug any other new problems that come up,
>>> instead of just emailing them to ncl-talk. We have a page to help you
>>> understand some of NCL's errors, and what causes them:
>>>
>>> http://www.ncl.ucar.edu/Document/Language/error_messages.shtml
>>>
>>> The particular error you're seeing can be found here:
>>>
>>> http://www.ncl.ucar.edu/Document/Language/error_messages.shtml#NumSubRHS
>>>
>>> As a side note, you are running a 3-year old version of NCL. I suggest
>>> that you upgrade to NCL V6.4.0.
>>>
>>> --Mary
>>>
>>>
>>>
>>> On Mon, Oct 16, 2017 at 12:52 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>> wrote:
>>>
>>>> I simply include the code (which you mentioned) were I was taking the
>>>> avg of the data as given below (please correct me if I did wrong)
>>>>
>>>>
>>>> ;----------------------------------------------------------------------
>>>> ; Main code
>>>> ;----------------------------------------------------------------------
>>>> dir = "./"
>>>> fnames = systemfunc("ls " + dir + "maiactaot*.nc")
>>>> print(fnames)
>>>> a = addfile(fnames,"r")
>>>> data = short2flt(a->Optical_Depth_055_grid1km)
>>>> printVarSummary (data)
>>>> printMinMax (data, 0)
>>>> print("-----")
>>>> nFill = num(ismissing(data))
>>>> print("nFill="+nFill)
>>>> print("-----")
>>>>
>>>> lat2d = a->GridLat_grid1km
>>>> lon2d = a->GridLon_grid1km
>>>> printMinMax (lat2d, 0)
>>>> printMinMax (lon2d, 0)
>>>> print("-----")
>>>>
>>>> ;---grid points of interest
>>>> ;---http://www.ncl.ucar.edu/Document/Functions/Contributed/g
>>>> etind_latlon2d.shtml
>>>> ; latv = (/22, 24.0, 24.0, 22.0, 22.0/)
>>>> ; lonv = (/76, 76.0, 78.0, 78.0, 76.0/)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *latv = (/ 22, 24/) lonv = (/ 76, 78 /) nm = getind_latlon2d
>>>> (lat2d, lon2d, latv, lonv) ilt1 = nm(0,0) ; start lat index ilt2 =
>>>> nm(1,0) ; start lon index iln1 = nm(0,1) ; end lat index iln2 =
>>>> nm(1,1) ; end lon index var_subset = var(ilt1:ilt2,iln1:iln2)
>>>> var_subset_avg = avg(var_subset)*
>>>>
>>>> print(nm)
>>>> print("-----")
>>>>
>>>> do k=0,dimsizes(latv)-1
>>>> n = nm(k,0)
>>>> m = nm(k,1)
>>>> print(lat2d(n,m)+" "+lon2d(n,m))
>>>> print(" "+data(:,n,m)) ; nearest grid point
>>>> at all time steps
>>>> print("-----")
>>>> end do
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *But still not getting the desired output as a single square box mean
>>>> value . It is showing the errors as*
>>>>
>>>> kunal at kunal-Vostro-1015:/media/Local Disk_/IIT_DELHI/2001/MAIACTAOT_TIME$
>>>> ncl extract1.ncl
>>>> Copyright (C) 1995-2014 - All Rights Reserved
>>>> University Corporation for Atmospheric Research
>>>> NCAR Command Language Version 6.2.1
>>>> The use of this software is governed by a License Agreement.
>>>> See http://www.ncl.ucar.edu/ for more details.
>>>>
>>>>
>>>> Variable: fnames
>>>> Type: string
>>>> Total Size: 4 bytes
>>>> 1 values
>>>> Number of Dimensions: 1
>>>> Dimensions and sizes: [1]
>>>> Coordinates:
>>>> (0) ./maiactaot.h00v02.20010040635-20011550640.nc
>>>>
>>>> Variable: data
>>>> Type: float
>>>> Total Size: 40320000 bytes
>>>> 10080000 values
>>>> Number of Dimensions: 3
>>>> Dimensions and sizes: [time | 7] x [YDim_grid1km | 1200] x
>>>> [XDim_grid1km | 1200]
>>>> Coordinates:
>>>> time: [8862.583333333314..12486.66666666669]
>>>> Number Of Attributes: 8
>>>> coordinates : GridLat_grid1km, GridLon_grid1km
>>>> hdfeos_name : Optical_Depth_055
>>>> projection : Albers Conical Equal_Area
>>>> unit : None
>>>> long_name : AOT at 0.55 micron
>>>> _FillValue_original : -28672
>>>> _FillValue : -28672
>>>> valid_range : ( -0.1, 5 )
>>>> (0) AOT at 0.55 micron: min=0 max=3.924
>>>> (0) -----
>>>> (0) nFill=6285271
>>>> (0) -----
>>>> (0) latitude: min=21.86737357453027 max=34.99855492029426
>>>> (0) longitude: min=64.23634233372005 max=79.4747290253718
>>>> (0) -----
>>>> fatal:["Execute.c":7863]:Number of subscripts on right-hand-side do
>>>> not match
>>>> number of dimensions of variable: (2), Subscripts used: (3)
>>>>
>>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 34 in
>>>> file extract1.ncl
>>>>
>>>> fatal:Variable (var_subset) is undefined
>>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 35 in
>>>> file extract1.ncl
>>>>
>>>>
>>>>
>>>>
>>>> Variable: nm
>>>> Type: integer
>>>> Total Size: 16 bytes
>>>> 4 values
>>>> Number of Dimensions: 2
>>>> Dimensions and sizes: [2] x [2]
>>>> Coordinates:
>>>> Number Of Attributes: 1
>>>> long_name : indices closest to specified LAT/LON coordinate pairs
>>>> (0,0) 1199
>>>> (0,1) 792
>>>> (1,0) 1199
>>>> (1,1) 1041
>>>> (0) -----
>>>> (0) 23.76603307545667 75.53995171540016
>>>> (0) 0.179
>>>> (1) 0.142
>>>> (2) -28672
>>>> (3) 0.169
>>>> (4) -28672
>>>> (5) -28672
>>>> (6) -28672
>>>> (0) -----
>>>> (0) 24.26559325846936 77.93996773594735
>>>> (0) -28672
>>>> (1) 0.393
>>>> (2) -28672
>>>> (3) 0.156
>>>> (4) 0.313
>>>> (5) -28672
>>>> (6) -28672
>>>> (0) -----
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Kunal Bali
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Sat, Oct 14, 2017 at 12:24 AM, Mary Haley <haley at ucar.edu> wrote:
>>>>
>>>>> Kunal,
>>>>>
>>>>> Please include the code where you are actually taking the average of
>>>>> your data using the information returned from getind_latlon2d.
>>>>>
>>>>> It's important to note that getind_latlon2d simply returns the
>>>>> individual index values that are closest to each of the lat/lon pairs that
>>>>> you gave it. It doesn't work in such a way that you give it a lat/lon box
>>>>> and it returns all the values in that box.
>>>>>
>>>>> That's what I was trying to illustrate with the wrf_gsn_10.ncl I
>>>>> created. I gave the function two corners of the box, and then using the
>>>>> two pairs of index values I got back, I was able to get all the values
>>>>> inside the box area of interest:
>>>>>
>>>>> lats = (/ min_lat, max_lat /)
>>>>> lons = (/ min_lon, max_lon /)
>>>>> nm = getind_latlon2d (lat2d, lon2d, lats, lons)
>>>>> ilt1 = nm(0,0) ; start lat index
>>>>> ilt2 = nm(1,0) ; start lon index
>>>>> iln1 = nm(0,1) ; end lat index
>>>>> iln2 = nm(1,1) ; end lon index
>>>>> var_subset = var(ilt1:ilt2,iln1:iln2)
>>>>> var_subset_avg = avg(var_subset)
>>>>>
>>>>> --Mary
>>>>>
>>>>>
>>>>> On Thu, Oct 12, 2017 at 1:19 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Dear Haley Ma'am,
>>>>>>
>>>>>> Thanks for providing the information and example.
>>>>>> But if I follow the getind_latlon2d function as I did, then it seems
>>>>>> like I followed the same procedure as given in the example
>>>>>> http://www.ncl.ucar.edu/Document/Functions/Contributed/getin
>>>>>> d_latlon2d.shtml
>>>>>>
>>>>>> But still I am not getting the mean of the grid box on every time
>>>>>> step or am I reading incorrectly the result ?
>>>>>>
>>>>>>
>>>>>> regards
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Oct 13, 2017 at 12:11 AM, Mary Haley <haley at ucar.edu> wrote:
>>>>>>
>>>>>>> Kunal,
>>>>>>>
>>>>>>> I created an example for you, showing three ways you can subset a
>>>>>>> WRF grid (since I already had a similar example). It shows how to use the
>>>>>>> getind_latlon2d function.
>>>>>>>
>>>>>>> You have to be careful with subsetting curvilinear data, because
>>>>>>> specifying a lat/lon box to take an average over can mean two
>>>>>>> different things. You will be able to see the difference when you look at
>>>>>>> the graphic.
>>>>>>>
>>>>>>> See example wrf_gsn_10.ncl at:
>>>>>>>
>>>>>>> http://www.ncl.ucar.edu/Applications/wrfgsn.shtml#ex10
>>>>>>>
>>>>>>> --Mary
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Oct 11, 2017 at 12:03 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Dear NCL users,
>>>>>>>>
>>>>>>>> Single point coordinates values of 23.0 N and 77.0 E is extracted
>>>>>>>> or print by using the script below
>>>>>>>>
>>>>>>>> ------------------------------------------------------------
>>>>>>>> ----------
>>>>>>>> ; Main code
>>>>>>>> ;-----------------------------------------------------------
>>>>>>>> -----------
>>>>>>>> dir = "./"
>>>>>>>> fnames = systemfunc("ls " + dir + "maiactaot*.nc")
>>>>>>>> print(fnames)
>>>>>>>> a = addfile(fnames,"r")
>>>>>>>> data = short2flt(a->Optical_Depth_055_grid1km)
>>>>>>>> nFill = num(ismissing(data))
>>>>>>>> lat2d = a->GridLat_grid1km
>>>>>>>> lon2d = a->GridLon_grid1km
>>>>>>>>
>>>>>>>> ;---grid points of interest
>>>>>>>> latv = (/23.0/)
>>>>>>>> lonv = (/77.0 /)
>>>>>>>>
>>>>>>>> nm = getind_latlon2d (lat2d,lon2d, latv, lonv)
>>>>>>>>
>>>>>>>> do k=0,dimsizes(latv)-1
>>>>>>>> n = nm(k,0)
>>>>>>>> m = nm(k,1)
>>>>>>>> print(lat2d(n,m)+" "+lon2d(n,m)) ; grid point location
>>>>>>>> print(" "+data(:,n,m)) ; nearest grid
>>>>>>>> point at all time steps
>>>>>>>> print("-----")
>>>>>>>> end do
>>>>>>>>
>>>>>>>>
>>>>>>>> NOW, I want to extract the square grid box of 100 km around the
>>>>>>>> coordinates (23N,77E) such as
>>>>>>>> latv = (/22, 24.0, 24.0, 22.0, 22.0/)
>>>>>>>> lonv = (/76, 76.0, 78.0, 78.0, 76.0 /)
>>>>>>>>
>>>>>>>>
>>>>>>>> after that I want to do the area mean of the grid box. So that I
>>>>>>>> can get one single point value of that grid box.
>>>>>>>> So when I replacing
>>>>>>>> latv = (/23.0/)
>>>>>>>> lonv = (/77.0/)
>>>>>>>>
>>>>>>>> with
>>>>>>>>
>>>>>>>> latv = (/22, 24.0, 24.0, 22.0, 22.0/)
>>>>>>>> lonv = (/76, 76.0, 78.0, 78.0, 76.0 /)
>>>>>>>>
>>>>>>>> then It's not giving mean of the square grid box.
>>>>>>>>
>>>>>>>> It shows the something like that (given below), which is incorrect.
>>>>>>>> So please let me know how can I get the square grid box mean and then
>>>>>>>> extract as asciiwrite or print?
>>>>>>>>
>>>>>>>> (0) 23.76603307545667 75.53995171540016
>>>>>>>> (0) 0.179
>>>>>>>> (1) 0.142
>>>>>>>> (2) -28672
>>>>>>>> (3) 0.169
>>>>>>>> (4) -28672
>>>>>>>> (5) -28672
>>>>>>>> (6) -28672
>>>>>>>> (0) -----
>>>>>>>> (0) 24.00322458681621 75.99551564353467
>>>>>>>> (0) 0.171
>>>>>>>> (1) 0.16
>>>>>>>> (2) -28672
>>>>>>>> (3) 0.17
>>>>>>>> (4) -28672
>>>>>>>> (5) -28672
>>>>>>>> (6) -28672
>>>>>>>>
>>>>>>>> etc..etc..
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> regards
>>>>>>>> Kunal Bali
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> ncl-talk mailing list
>>>>>>>> ncl-talk at ucar.edu
>>>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> ncl-talk mailing list
>>>>>> ncl-talk at ucar.edu
>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>
>>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> ncl-talk mailing list
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>>>
>>
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>
>
> Guido Cioni
> http://guidocioni.altervista.org
>
>
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