[ncl-talk] set_dimension_query
Rick Brownrigg
brownrig at ucar.edu
Sat Sep 30 10:45:31 MDT 2017
Hi,
This file is an interesting and challenging one to geo-reference. Without
proper documentation on how the file is constructed/encoded, all of what
follows is speculation. But I'm fairly confident it is sound.
In the group GRID_1, there are these parameters:
GridName="grid1km"
XDim=1200
YDim=1200
UpperLeftPointMtrs=(-3450000.000000,1600000.000000)
LowerRightMtrs=(-2250000.000000,400000.000000)
Projection=GCTP_ALBERS
ProjParams=(0,0,21030000,41000000,102000000,23000000,0,0,0,0,0,0,0)
SphereCode=12
GridOrigin=HDFE_GD_UL
GROUP=Dimension
END_GROUP=Dimension
The name suggests a 1KM grid, and as such, by its resolution, it should
span 1200KM. Indeed, from the corner points:
In X: (-3450000 - -2250000) = a span of 1200000meters; divided by
xres=1200, yields 1000meter grid cells
In Y: (1600000 - 400000) = 1200000meters; div by yres=1200 yields
1000meter grid cells
So everything is consistent so far. The GCTP_ALBERS suggest the grid was
constructed based upon an ALBERS projection, using the GCTP library. The
ProjParams give further details:
ProjParams=(0,0,21030000,41000000,102000000,23000000,0,0,0,0,0,0,0)
Again, without documentation, this is speculation, but looking at
pg13/appendexD in:
https://www.ngs.noaa.gov/PUBS_LIB/GeneralCartographicTransformationPackage_v2_TR_NOS124_CGS9.pdf
for the Albers projection, the first 2 values appear to be semimajor axis
of ellipsoid, and eccentricity. Both are zero, implying defaults of
Clarke's 1866 ellipsoid and spherical earth (which seems to be an oymoron?
I'm confused about that)
The next 6 values might be:
lat of 1st standard parallel
lat of 2nd standard parallel
lon of central meridian
lat of projection's origin
false easting (zero in this case)
false northing (zero)
the remaining zeros don't seem to apply.
NCL does not have an public interface to GCTP, but there is an undocumented
interface to the well-known proj4 library. The trick here is to use it to
convert from meters-on-the ground units into lat/lon. The first step is to
construct arrays representing the grid's position in meters. In the X
direction, if we did
x = fspan(-3450000., -2250000, 1200)
we get an array of 1201, which is wrong. I speculate that for a grid of
1200, those values represent the total *spatial extent* of the grid, but
that the data are based upon cell centers, not corners. Thus something like:
x = fspan(-3450000.+500., -2250000.-500., 1200)
y = fspan(1600000.-500., 400000.+500., 1200)
A 1km grid cannot obviously be constant spacing in longitude, so
ultimately, your coordinate arrays are going to be curvilinear:
x := conform_dims((/1200, 1200/), x, 1)
y := conform_dims((/1200, 1200/), y, 0)
NOTE: THIS ASSUMES THE GRID IS ROW MAJOR, WEST-->EAST, NORTH-->SOUTH
The undocumented NCL function "transform_coordinates" takes a proj4
source-porjection string, dest-proj string, x, y, z 1D arrays of type
double, and returns the results in the x,y,z arrays. I won't go into the
details of the proj-strings. We want something like:
src = "+proj=aea +lat_0=23.0 +lat_1=21d03m +lat_2=41 +lon_0=102
+ellps=clrk66"
dst = "+proj=latlon +ellps=sphere"
x := flt2dble(ndtooned(x))
y := flt2dble(ndtooned(y))
z = x ; A quick-n-dirty way to get an empty Z array of same
dimensions/type
z = 0. ;
transform_coordinate(src, dst, x, y, z)
; convert back to curvilinear coord arrays
lon = onedtond(x, (/1200, 1200/))
lat = onedtond(y, (/1200, 1200/))
>From here, you have to associate the lat/lon coordinate arrays with the
variables you want to plot, as Adam and other previously described.
Attached is a script and example plot of the resultant grid. Please let the
group know if this appears to be the correct area-of-interest.
Rick
On Fri, Sep 29, 2017 at 11:45 AM, Rick Brownrigg <brownrig at ucar.edu> wrote:
> Hi,
>
> I do not know for certain without examining the file, but it looks like
> those values are map-projection parameters, from which curvilinear grid was
> generated as equal-area grid cells in lat/lon spac.
>
> Rick
>
> On Fri, Sep 29, 2017 at 10:16 AM, Kunal Bali <kunal.bali9 at gmail.com>
> wrote:
>
>> Thanks for all the suggestions and help Adam Sir. Now the data is showing
>> over the Indian region.
>> but one thing I need to confirm here.
>>
>> Some values in the form of UpperLeftPointMtrs and LowerRightMtrs are
>> given in the file ((in the original hdf file) ) description along with X
>> YDim.
>>
>> So, does these value interfer while creating the lat lon dimensions
>> during conversion netcdf from hdf?
>>
>> Sould these values be consider or we can ignore these values?
>>
>>
>> group: latlon {
>> variables:
>> short _HDFEOS_CRS;
>> :Projection = "GCTP_ALBERS";
>> :*UpperLeftPointMtrs* = -3450000.0, 1600000.0; // double
>> *:LowerRightMtrs* = -2250000.0, 400000.0; // double
>> :ProjParams = 0.0, 0.0, 2.103E7, 4.1E7, 1.02E8, 2.3E7, 0.0, 0.0,
>> 0.0, 0.0, 0.0, 0.0, 0.0; // double
>> :SphereCode = "12";
>>
>> group: Data_Fields {
>> dimensions:
>> YDim = 1200;
>> XDim = 1200;
>> variables:
>> float lat(YDim=1200, XDim=1200);
>>
>> float lon(YDim=1200, XDim=1200);
>>
>>
>>
>>
>>
>>
>> Regards
>> Kunal Bali
>>
>>
>>
>>
>> On Thu, Sep 28, 2017 at 9:27 PM, Adam Phillips <asphilli at ucar.edu> wrote:
>>
>>> Hi Kunal,
>>> As the documentation states, latGlobeFo (lonGlobeFo) generates
>>> latitudes (longitudes) and associated metadata for a *global* fixed
>>> offset grid.
>>> https://www.ncl.ucar.edu/Document/Functions/Contributed/latGlobeFo.shtml
>>> https://www.ncl.ucar.edu/Document/Functions/Contributed/lonGlobeFo.shtml
>>> If you need to create coordinates for a regional grid, then you will
>>> have to do it by hand. For example, if you know your data are equally
>>> spaced in the both the latitude and longitude direction from 0:40N, 60:100E
>>> (for example), you can set up your coordinates like this:
>>>
>>> lat = fspan(0,40,1200)
>>> lon = fspan(60,100,1200)
>>> print(lat) ; check that these are the correct coordinates
>>> print(lon) ; check that these are the correct coordinates
>>> lat at units = "degrees_north"
>>> lat!0 = "lat"
>>> lat&lat = lat
>>> lon at units = "degrees_east"
>>> lon!0 = "lon"
>>> lon&lon = lon
>>> var!0 = "lat" ; you can name these dimensions whatever you want..
>>> var!1 = "lon"
>>> var&lat = lat ; but make sure you refer to the correct named
>>> dimensions
>>> var&lon = lon
>>>
>>> The above is similar to what latGlobeFo/lonGlobeFo do for global grids.
>>> Hope that helps. If you have further questions please respond to ncl-talk.
>>> Adam
>>>
>>> On Tue, Sep 26, 2017 at 10:26 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>> wrote:
>>>
>>>> Thanks for all the suggestions Dennis sir.
>>>> But now I have come to know that the dimensions
>>>>
>>>> nlat=1200
>>>> nlon=1200
>>>>
>>>> are belongs to only of Indian region.
>>>>
>>>> And the code I am using below is not displaying the data over Indian
>>>> region.
>>>>
>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>> lat = lat(::-1)
>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>> lon&lon = lon
>>>>
>>>> So please help me regarding this issue.
>>>>
>>>> regards
>>>> Kunal Bali
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Sep 19, 2017 at 10:36 PM, Dennis Shea <shea at ucar.edu> wrote:
>>>>
>>>>> Ditto what Marston posted.
>>>>>
>>>>> ===
>>>>> Please look at NCL's FAQ.
>>>>>
>>>>> [1] Click "Support" at top of page
>>>>> [2] Click FAQ
>>>>>
>>>>> I think it would be instructive to look at all of the topics.
>>>>>
>>>>> For example:
>>>>>
>>>>> *Error messages and other issues*
>>>>> Look at #7
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Sep 19, 2017 at 3:03 AM, Marston Johnston <shejo284 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> It tells you in the warning message, exactly what to do to remove the
>>>>>> warning.
>>>>>>
>>>>>> If you want to improve you coding skills, it would better to
>>>>>> understand why the warning is occurring in the first place: dimension 0 and
>>>>>> 1 of the variable you are passing has no names or the names do not match
>>>>>> the variable on the lhs.
>>>>>>
>>>>>>
>>>>>>
>>>>>> /M
>>>>>>
>>>>>>
>>>>>>
>>>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>>
>>>>>> Marston S. Ward, PhD
>>>>>>
>>>>>> Department of Earth Sciences
>>>>>>
>>>>>> University of Gothenburg, Sweden
>>>>>>
>>>>>> Email: marston.johnston at gu.se
>>>>>>
>>>>>> SkypeID: marston.johnston
>>>>>>
>>>>>> Phone: +46-31-7864901 <+46%2031%20786%2049%2001>
>>>>>>
>>>>>> Only the fruitful thing is true!
>>>>>>
>>>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *From: *ncl-talk <ncl-talk-bounces at ucar.edu> on behalf of Kunal Bali
>>>>>> <kunal.bali9 at gmail.com>
>>>>>> *Date: *Tuesday, 19 September 2017 at 10:50
>>>>>> *Cc: *"ncl-talk at ucar.edu" <ncl-talk at ucar.edu>
>>>>>> *Subject: *Re: [ncl-talk] set_dimension_query
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thank you for providing this information.
>>>>>>
>>>>>> It's working. The script given below is now able to convert multiple
>>>>>> files into .netcdf with the desired file name.
>>>>>> However, on the same time, it also shows some warnings. But noted
>>>>>> that, I am successfully creating the multiple files into the netcdf. I just
>>>>>> need to know that how can I remove these warnings?
>>>>>>
>>>>>> warning:VarVarWrite: Dimension names for dimension number (0) don't
>>>>>> match, assigning name of rhs dimension to lhs and overwriting coordinate
>>>>>> variable, use "(/../)" if this change is not desired
>>>>>> warning:VarVarWrite: Dimension names for dimension number (1) don't
>>>>>> match, assigning name of rhs dimension to lhs and overwriting coordinate
>>>>>> variable, use "(/../)" if this change is not desired
>>>>>> warning:["Execute.c":8640]:Execute: Error occurred at or near line
>>>>>> 22 in file netcdf2.ncl
>>>>>>
>>>>>>
>>>>>>
>>>>>> ;-----------------------------------------------------------
>>>>>> -----------
>>>>>>
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>>>>>
>>>>>> begin
>>>>>> ;---Read data
>>>>>>
>>>>>> diri = "/Users/Pushp/Desktop/test/" ; input directory
>>>>>> fili = systemfunc("cd "+diri+" ; ls MAIACTAOT.h00v02*hdf")
>>>>>> nfili = dimsizes(fili)
>>>>>> print("nfili="+nfili)
>>>>>>
>>>>>>
>>>>>> dirnc = "/Users/Pushp/Desktop/test/" ; output (netCDF)
>>>>>> directory
>>>>>>
>>>>>> do nf=0,nfili-1
>>>>>> pthi = diri+fili(nf)
>>>>>> f = addfile(pthi,"r")
>>>>>>
>>>>>> var = short2flt(f->Optical_Depth_055(:,:))
>>>>>>
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> ; lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>> var!0 = "lat" ; you can name these dimensions whatever you
>>>>>> want..
>>>>>> var!1 = "lon"
>>>>>> var&lat = lat ; but make sure you refer to the correct
>>>>>> named dimensions
>>>>>> var&lon = lon
>>>>>>
>>>>>>
>>>>>> filroot = str_get_cols(fili(nf), 0, 27) ; eg:
>>>>>> "MAIACTAOT.h00v02.20000570505"
>>>>>> filnc = filroot+".nc"
>>>>>> pthnc = dirnc + filnc
>>>>>>
>>>>>> system("/bin/rm -f "+pthnc)
>>>>>> ncdf = addfile(pthnc,"c") ; open new netCDF file
>>>>>>
>>>>>>
>>>>>> end do ; end 'nf' loop
>>>>>>
>>>>>> ; system("/bin/rm -f simple2.nc")
>>>>>> ; ncdf = addfile("simple2.nc" ,"c") ; open output netCDF file
>>>>>>
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> ; create global attributes of the file (optional)
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> fAtt = True ; assign file attributes
>>>>>> fAtt at title = "NCL Simple Approach to netCDF Creation"
>>>>>> fAtt at source_file = "original-file.nc"
>>>>>> fAtt at Conventions = "None"
>>>>>> fAtt at creation_date = systemfunc ("date")
>>>>>> fileattdef( ncdf, fAtt ) ; copy file attributes
>>>>>>
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> ; make time an UNLIMITED dimension; recommended for most
>>>>>> applications
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> filedimdef(ncdf,"time",-1,True)
>>>>>>
>>>>>> ; ncdf->var&lat = lat
>>>>>> ; ncdf->var&lon = lon
>>>>>> ncdf->var = var
>>>>>>
>>>>>> end
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>> Research Scholar
>>>>>>
>>>>>> Radio & Atmospheric Science Division
>>>>>>
>>>>>> CSIR - National Physical Laboratory
>>>>>>
>>>>>> New Delhi - 110012
>>>>>>
>>>>>> India
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 18, 2017 at 9:04 PM, Dennis Shea <shea at ucar.edu> wrote:
>>>>>>
>>>>>> Loop over the files ...
>>>>>>
>>>>>>
>>>>>> diri = "/media/Local Disk/NPL/MODIS_FPC/" ; input directory
>>>>>>
>>>>>> fili = systemfunc("cd "+diri +; ls MAIACTAOT.h00v02*hdf")
>>>>>>
>>>>>> nfili = dimsizes(fili)
>>>>>>
>>>>>> print("nfili="+nfili)
>>>>>>
>>>>>> dirnc = "/media/Local Disk/NPL/MODIS_FPC/" ; output (netCDF)
>>>>>> directory
>>>>>>
>>>>>>
>>>>>>
>>>>>> do nf=0,nfili-1
>>>>>>
>>>>>> pthi = diri+fili(nf)
>>>>>>
>>>>>> f = addfile(pthi,"r")
>>>>>>
>>>>>> ....
>>>>>>
>>>>>> filroot = *str_get_cols*(fili(nf), 0, 27) ; eg:
>>>>>> "MAIACTAOT.h00v02.20000570505"
>>>>>>
>>>>>> filnc = filroot+".nc"
>>>>>>
>>>>>> pthnc = dirnc + filnc
>>>>>>
>>>>>> system("/bin/rm -f "+pthnc)
>>>>>> ncdf = addfile(pthnc,"c") ; open new netCDF file
>>>>>>
>>>>>> ....
>>>>>>
>>>>>> end do ; end 'nf' loop
>>>>>>
>>>>>>
>>>>>> =====
>>>>>>
>>>>>> If there is something you do not understand use some print statements.
>>>>>>
>>>>>> Become familiar with the 'string' category. Look at all the functions.
>>>>>>
>>>>>> https://www.ncl.ucar.edu/Document/Functions/string.shtml
>>>>>>
>>>>>> Please read the documentation for the function used above
>>>>>>
>>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/str_get
>>>>>> _cols.shtml
>>>>>>
>>>>>> Good Luck
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 18, 2017 at 6:11 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thnks for the reply.
>>>>>>
>>>>>>
>>>>>>
>>>>>> that will change the name of only one file. isn't it. but what about
>>>>>> the other files
>>>>>>
>>>>>> I have 365 files in one directory and I need to change all the file
>>>>>> name one by one.
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 18, 2017 at 5:14 PM, Dennis Shea <shea at ucar.edu> wrote:
>>>>>>
>>>>>> Really?
>>>>>>
>>>>>> Change:
>>>>>> system("/bin/rm -f simple.nc")
>>>>>> ncdf = addfile("simple.nc" ,"c")
>>>>>>
>>>>>> To:
>>>>>> system("/bin/rm -f MAIACTAOT.h00v02.20000570505.nc
>>>>>> <http://simple.nc>")
>>>>>> ncdf = addfile("MAIACTAOT.h00v02.20000570505.nc" ,"c")
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 18, 2017 at 12:37 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thanks, it worked.
>>>>>>
>>>>>> one more question is that.
>>>>>>
>>>>>> I used the code (given below). So it gives simple.nc name as an
>>>>>> output file.
>>>>>>
>>>>>> ncdf = addfile("simple.nc" ,"c")
>>>>>>
>>>>>> If I want to keep the original file name with the output file name
>>>>>> then what should I do?
>>>>>>
>>>>>> I mean the original file name is MAIACTAOT.h00v02.20003660700.hdf
>>>>>>
>>>>>> Now I want to create my netcdf file name as
>>>>>> MAIACTAOT.h00v02.20003660700.nc NOT simple.nc.
>>>>>>
>>>>>> I can not simply write simple.nc file name because I have many
>>>>>> files.
>>>>>>
>>>>>> e.g I have one directory having 365 .hdf file. So I need to convert
>>>>>> all the hdf file to netcdf file at once with the same name of original file
>>>>>> names.
>>>>>>
>>>>>> I hope you have got my query.
>>>>>>
>>>>>> please let me know that too.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thank You
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Sep 14, 2017 at 9:09 PM, Adam Phillips <asphilli at ucar.edu>
>>>>>> wrote:
>>>>>>
>>>>>> Hi Kunal,
>>>>>>
>>>>>> It looks to me like your latitudes are flipped. You are setting up
>>>>>> and assigning your coordinate lat/lon variables in this coding:
>>>>>>
>>>>>>
>>>>>>
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>>
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>>
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>> var!0 = "lat" ; you can name these dimensions whatever you want..
>>>>>> var!1 = "lon"
>>>>>> var&lat = lat ; but make sure you refer to the correct named
>>>>>> dimensions
>>>>>> var&lon = lon
>>>>>>
>>>>>>
>>>>>>
>>>>>> Assuming I'm right on your latitudes being the issue, one of the
>>>>>> following two modifications should work:
>>>>>>
>>>>>> Delete this line:
>>>>>>
>>>>>> lat = lat(::-1)
>>>>>>
>>>>>>
>>>>>>
>>>>>> If the above doesn't fix it, try this:
>>>>>>
>>>>>> Change this:
>>>>>>
>>>>>> lat = lat(::-1)
>>>>>>
>>>>>> to this:
>>>>>>
>>>>>> lat = lat(::-1)
>>>>>>
>>>>>> lat&lat = lat
>>>>>>
>>>>>>
>>>>>>
>>>>>> If you continue to have issues please respond to ncl-talk.
>>>>>>
>>>>>> Adam
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 12:35 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> For direct output as a netcdf format, I used the script given below.
>>>>>> It produced the netcdf file easily. But the netcdf file and original hdf
>>>>>> file both showing the different results. The data pattern is shifted. I
>>>>>> mean it may be related to the lat lon position. please see the attached
>>>>>> file, you will understand. And please let me know which one is correct.
>>>>>>
>>>>>> ;-----------------------------------------------------------
>>>>>> -----------
>>>>>>
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>>>>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>>>>>
>>>>>> begin
>>>>>> ;---Read data
>>>>>> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.h
>>>>>> 00v02.20000570505.hdf","r")
>>>>>> var = short2flt(a->Optical_Depth_055(:,:))
>>>>>> ; short2flt(a[:]->noxfire)
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>> var!0 = "lat" ; you can name these dimensions whatever you
>>>>>> want..
>>>>>> var!1 = "lon"
>>>>>> var&lat = lat ; but make sure you refer to the correct
>>>>>> named dimensions
>>>>>> var&lon = lon
>>>>>>
>>>>>> system("/bin/rm -f simple.nc")
>>>>>> ncdf = addfile("simple.nc" ,"c") ; open output netCDF
>>>>>> file
>>>>>>
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> ; create global attributes of the file (optional)
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> fAtt = True ; assign file attributes
>>>>>> fAtt at title = "NCL Simple Approach to netCDF Creation"
>>>>>> fAtt at source_file = "original-file.nc"
>>>>>> fAtt at Conventions = "None"
>>>>>> fAtt at creation_date = systemfunc ("date")
>>>>>> fileattdef( ncdf, fAtt ) ; copy file attributes
>>>>>>
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> ; make time an UNLIMITED dimension; recommended for most
>>>>>> applications
>>>>>> ;===========================================================
>>>>>> ========
>>>>>> filedimdef(ncdf,"time",-1,True)
>>>>>> ncdf->var = var
>>>>>>
>>>>>> end
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 11:27 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> No problem, I sorted out.
>>>>>>
>>>>>> Just changed short to float.
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>> Research Scholar
>>>>>>
>>>>>> Radio & Atmospheric Science Division
>>>>>>
>>>>>> CSIR - National Physical Laboratory
>>>>>>
>>>>>> New Delhi - 110012
>>>>>>
>>>>>> India
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 11:24 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thanks for providing this information.
>>>>>>
>>>>>> Also, I would like to mention that when I plot this data. The values
>>>>>> are not in the domain. I mean the real values lie in-between 0 to 1 but
>>>>>> here it is reaching to 400.
>>>>>>
>>>>>> So, how to correct the values?
>>>>>>
>>>>>> Description of the variable is
>>>>>>
>>>>>> short Optical_Depth_055(YDim=1200, XDim=1200);
>>>>>> :long_name = "AOT at 0.55 micron";
>>>>>> :scale_factor = 0.001; // double
>>>>>> :add_offset = 0.0; // double
>>>>>> :unit = "None";
>>>>>> :_FillValue = -28672S; // short
>>>>>> :valid_range = -100S, 5000S; // short
>>>>>>
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 10:28 PM, Adam Phillips <asphilli at ucar.edu>
>>>>>> wrote:
>>>>>>
>>>>>> Hi Kunal,
>>>>>>
>>>>>> Yes, clicking on the output netCDF link from the Applications page:
>>>>>>
>>>>>> http://www.ncl.ucar.edu/Applications/o-netcdf.shtml
>>>>>>
>>>>>> I would recommend following the inefficient method #1. Unless you are
>>>>>> writing a file with many large variables, the inefficient method works just
>>>>>> fine.
>>>>>>
>>>>>> http://www.ncl.ucar.edu/Applications/method_1.shtml
>>>>>>
>>>>>> Good luck,
>>>>>>
>>>>>> Adam
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 10:25 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thank you so much, it worked
>>>>>>
>>>>>> I want to know one more thing.
>>>>>> After rearranging the dimensions can we now convert (or write) this
>>>>>> arranged file into netcdf format?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 8:55 PM, Adam Phillips <asphilli at ucar.edu>
>>>>>> wrote:
>>>>>>
>>>>>> Hi Kunal,
>>>>>>
>>>>>> I think you just need to rearrange the order of your lines and tweak
>>>>>> a couple of lines. As the error message states, lat is not defined in your
>>>>>> 3rd line and you are referring to it as if it is.Try this:
>>>>>>
>>>>>> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.h
>>>>>> 00v02.20000570505.hdf","r")
>>>>>> var = a->Optical_Depth_055(:,:)
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>>
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>> var!0 = "lat" ; you can name these dimensions whatever you want..
>>>>>> var!1 = "lon"
>>>>>>
>>>>>> var&lat = lat ; but make sure you refer to the correct named
>>>>>> dimensions
>>>>>>
>>>>>> var&lat = lon
>>>>>>
>>>>>> ;var&XDim_grid1km = lat
>>>>>> ;var&YDim_grid1km = lon
>>>>>>
>>>>>>
>>>>>> If you have any further questions please respond to the ncl-talk
>>>>>> email list.
>>>>>>
>>>>>> Adam
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 8:38 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Dear NCL
>>>>>>
>>>>>> I have a file with the variable summary. The dimensions are in 2D.
>>>>>>
>>>>>> ncl 2> printVarSummary(var)
>>>>>>
>>>>>> Variable: var
>>>>>> Type: short
>>>>>> Total Size: 2880000 bytes
>>>>>> 1440000 values
>>>>>> Number of Dimensions: 2
>>>>>> Dimensions and sizes: [*YDim_grid1km | 1200] x [XDim_grid1km |
>>>>>> 1200]*
>>>>>> Coordinates:
>>>>>> Number Of Attributes: 7
>>>>>> long_name : AOT at 0.55 micron
>>>>>> scale_factor : 0.001
>>>>>> add_offset : 0
>>>>>> unit : None
>>>>>> _FillValue : -28672
>>>>>> valid_range : ( -100, 5000 )
>>>>>> hdf_name : Optical_Depth_055
>>>>>>
>>>>>> I am trying to read the dimensions of this file as
>>>>>>
>>>>>> begin
>>>>>> ;---Read data
>>>>>> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.h
>>>>>> 00v02.20000570505.hdf","r")
>>>>>>
>>>>>> var = a->Optical_Depth_055(:,:)
>>>>>>
>>>>>> var&XDim_grid1km = lat
>>>>>> var&YDim_grid1km = lon
>>>>>>
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>>
>>>>>> var!0 = "lat"
>>>>>> var!1 = "lon"
>>>>>>
>>>>>>
>>>>>> But the error appeared as
>>>>>> *fatal:Variable (lat) is undefined*
>>>>>>
>>>>>>
>>>>>>
>>>>>> So, could anyone please let me know that how to read dimension of
>>>>>> this file.
>>>>>>
>>>>>> Thank You
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> 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
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> Adam Phillips
>>>>>>
>>>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>>>>
>>>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>>>>>> <%28303%29%20497-1726>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> ncl-talk mailing list
>>>>>> ncl-talk at ucar.edu
>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> Adam Phillips
>>>>>>
>>>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>>>>
>>>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>>>>>> <%28303%29%20497-1726>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> ncl-talk mailing list
>>>>>> ncl-talk at ucar.edu
>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> Adam Phillips
>>>>>>
>>>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>>>>
>>>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>>>>>> <%28303%29%20497-1726>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> 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 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
>>>> ncl-talk at ucar.edu
>>>> List instructions, subscriber options, unsubscribe:
>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>
>>>>
>>>
>>>
>>> --
>>> Adam Phillips
>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726 <(303)%20497-1726>
>>>
>>> <http://www.cgd.ucar.edu/staff/asphilli>
>>>
>>
>>
>> _______________________________________________
>> ncl-talk mailing list
>> ncl-talk at ucar.edu
>> List instructions, subscriber options, unsubscribe:
>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>
>>
>
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