[Koha] Subject Cloud

[Rubén Fernández Asensio]

Hi all,

I run a small library and I want to allow OPAC users to browse our 
holdings by topic. Most of our holdings use the 653a MARC21 field as 
subject headings.
I enabled the "OPAC Cloud" preference. Then I tried to build the tag 
database as instructed:
	export KOHA_CONF=/etc/koha/sites/biblioteko/koha-conf.xml; 
/usr/share/koha/bin/cronjobs/build_browser_and_cloud.pl -t 653a -c

The command exited successfully, as far as I could tell. Now the OPAC 
shows a "Subject Cloud" link, but it only displays the following text:

"Note: This feature only available to French catalogs where ISBD 
subjects have been populated, and an index built by separate script."

According to HEA (https://hea.koha-community.org/systempreferences) at 
least 89 libraries around the world use this feature, and I can't 
believe they're all French language libraries. What are the exact 
requirements to have this working? Does any of you use this feature, and 
can guide me step by step?

Rubén Fernández