On topic profiles, add country-level citation network

[Daniel-Mietchen]

Ideally, the entries in the graph would link directly to the country/ topic profiles, e.g. as per
https://tools.wmflabs.org/scholia/country/Q668/topic/Q10737 .

[Daniel-Mietchen]

Here is a draft query for such a country-level citation network, using Zika virus as an example:

[Daniel-Mietchen]

On that basis, I played around with a suitable number of connections, and 30 to 50 seems to be useful for most cases.

[egonw]

What happens for multi-country articles that cite another multi-country article? I can imagine these graphs to very quickly become a network blob.

[Daniel-Mietchen]

@egonw In the query used in the PR at #1102 , there is a limit of the number of connections displayed, which I arbitrarily set to 42 after playing around with values between about 10 and about 100 for well-curated topics.

[fnielsen]

This is an interesting graph. It must be expensive if there are many papers. Wikipedia and Machine learning and biophysics worked fast though.

[fnielsen]

It is now running, e.g., at https://tools.wmflabs.org/scholia/topic/Q9035