Read covid data (json)

I wonder if there is any tool to convert
to ROOT tree?

Regards. Valeriy

_ROOT Version:git head
_Compiler:vs2019 head

This was discussed on this forum already for instance here.

Thanks Olivier.
Can it be done in more “automatic way”?

The problem:

  1. one day covid data is 57 Mbytes plane table
    covid-19-data/owid-covid-codebook.csv (json scheema)

  2. for ~2 years = (57 Mb)x(700 days) ~ 40 Gb of raw data
    an automatic sequential (read JSON)/(write ROOT) proc desperately needed.

  3. it would be nice to have an automatic bot to update this output ROOT file daily.

Any ideas?

If there is a brave volunteer who will not afraid of this boring job? :slight_smile:

I do not know. May be @linev has some ideas.

Hi Valeriy,

ROOT does not provide generic reader of JSON data into TTree - although
internally we do use JSON parser but only for ROOT-created JSON structures. In principle, one could implement this and any volunteer is welcome.


Hi Sergey,
after 2006 when I was a ROOT evangelist I’m for a long time a C# and Kotlin guy. There is Newtonsoft.Json and async HttpClient which can do Get->Parse->Deserialize JSON quite easy.
If there are any news about interop C#(PowerShell) <-> ROOT bridge?
I know about ROOT.NET: Build .NET wrappers for the ROOT scientific data analysis toolkit ( but not sure if it helps.


Sergey, Bertrand, could describe the status and progress of JSROOT development?

Recently I found very useful guide on it at
ROOT: documentation/JSROOT/ | Fossies
BUT unfortunately I do not see anything similar to it on the main ROOT site. It’s a pity.

Hi Valeriy,

With some effort one should be able to find link on site:

But up-to-date source is in repository:


Hi Valeriy,
The ROOT related manual can be found here: Topical Manuals - ROOT
We will revisit this soon.

I just found out that this page had no proper JSROOT link.
I add proper link now.

1 Like

it was not easy to find it :frowning:
I suggest to put JSROOT demos directly to
Galleries of images produced with ROOT - ROOT
and to add the link to the guide directly there
JavaScript ROOT

I am not sure about the JSROOT galerie… but why not.

he-he … :slight_smile:
the whole covid data for all countries for the period
from 2020-02-14 to 2021-07-07 weights only ~57 Mbytes.

I’m going to prepare PowerShell7&ROOT scripts
which will put the whole covid data to the ROOT tree/file.

PowerShell7 can run on windows, linux, mac osx and Android.

btw, is it possible to run ROOT on smartphones, tablets
with Android
on board?