[R-sig-Geo] Extract Lightning Flash Time series data

[Edzer Pebesma]

Someone tried to pack a lot of different things in that netcdf file! Is 
there one particular variable that is of main interest to you? AFAICT 
the primary observations seem like (long,lat,time,something_measured)
sets, as if along a trajectory. Finding the variables that depend on 
dimension viewtime_dim give you 2097 records of them.

Package stars is not so well equiped for one-dimensional arrays - sf 
would be more suitable in terms of data structure but GDAL doesn't seem 
to understand the file to contain vector (POINT) geometries.

I think I would go for using packages like RNetCDF or ncdf4 and 
extracting the one-dimensional variables of interest, then cbind-ing them.

On 11/09/2022 07:16, sownal chand wrote:
> Thanks Michael
> 
> 
> But i will try out your approach and let see how it goes.
> 
> Kind regards
> Sownalc
> 
> On Sun, Sep 11, 2022, 16:51 Michael Sumner <mdsumner using gmail.com> wrote:
> 
>> I don't understand this file structure yet, but you might try tidync:
>>
>> library(tidync)
>> ## open the file and get a summary of all vars and the dimensions they use
>> (nc <- tidync::tidync("TRMM_LIS.nc"))
>>
>> See how viewtime_lat, viewtime_lon (and others) exist on the grid
>> identified by "D0" (other grids include multiple dims and so have
>> identifiers like "D1,D2" - this concept doesn't exist in NetCDF itself but
>> tidync wanted to group variables by the dims they use).
>>
>> The grid "D0" is not active by default, so you can do
>>
>> nc |> activate("D0")
>>
>> (everything is lazy up to this point, no data has been read)
>>
>> Convert to dataframe with
>>
>> nc |> activate("D0") |> hyper_tibble()
>>
>> You can use hyper_array() to get in native array format with some informal
>> metadata on the output.
>>
>> HTH, otherwise package stars has another approach and some similar
>> facilities.  I often use tidync just to understand what's there, but I
>> might craft a solution with a different tool after I've explored. RNetCDF
>> will give you direct low level access to this format, for example.
>>
>> Cheers, Mike
>>
>>
>>
>>
>> On Sun, Sep 11, 2022 at 1:22 PM sownal chand <sownalchandfms using gmail.com>
>> wrote:
>>
>>> Hello Sir/Madam,
>>>
>>> I have downloaded a TRMM_LIS.nc File with lightning time series data and
>>> was trying to extract it into a CSV file but I am not sure on how to do
>>> it.
>>>
>>> I am also attaching the TRMM_LIS file via this link:
>>>
>>> https://drive.google.com/drive/u/0/folders/19nJNwPKlJaPlkHn_NGzmjMHMaoUevH04
>>>
>>> Request if someone can guide me and thanking you in advance
>>> sownalc
>>>
>>>          [[alternative HTML version deleted]]
>>>
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>>>
>>
>>
>> --
>> Michael Sumner
>> Software and Database Engineer
>> Australian Antarctic Division
>> Hobart, Australia
>> e-mail: mdsumner using gmail.com
>>
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Edzer Pebesma
Institute for Geoinformatics
Heisenbergstrasse 2, 48151 Muenster, Germany
Phone: +49 251 8333081