Group catalogue: downloading only certain columns

Diego Sotillo Ramos
  • 14 Sep '19

Hi, Dylan:

  1. following the examples on the web I know how to download a groups catalogue, with

wget -nd -nc -nv -e robots=off -l 1 -r -A hdf5 --content-disposition --header="API-Key: MY_KEY" "http://www.tng-project.org/api/Illustris-3/files/groupcat-135/?format=api"

but I need only certain columns (let's say, for example, GroupPos, Group_R_Crit200 for the halos and SubhaloGrNr, SubhaloPos, SubhaloMassType, SubhaloSFR for the subhalos )

--> is there a way to download only that part of the catalogue? Or to download only the rows following, for example, the condition SubhaloSFR>0?

Thank you in advance!
Diego

Dylan Nelson
  • 14 Sep '19

Hi Diego,

Yes you can download single fields of the group catalog, search for "subset_query" on the API docs page.

For example

http://www.tng-project.org/api/Illustris-3/files/groupcat-135/?Group=GroupPos

should work.

You can't selectively download rows according to a condition, but of course you can search online using the API with a condition, and then parse the results, e.g.

www.tng-project.org/api/Illustris-3/snapshots/135/subhalos/?sfr__gt=0
Diego Sotillo Ramos
  • 14 Sep '19

Hi, Dylan:

I have found all the details on http://www.tng-project.org/data/docs/api/ and, as you said, it works!

Thank you,
Diego

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