[Taginfo-dev] New functions

[Jochen Topf]

Hi!

There are a few new functions available in taginfo:
- "Similar" tab in key view and "Similar keys" report. Similarity in this
  context means one key is a substring of the other (ignoring case) or
  the Levenshtein distance between keys is <= 3. Keys with three characters or
  less are ignored. The "Similar" tab reports all those keys similar to the
  given key, the "Similar keys" report only shows rarely used keys that are
  very similar to common keys. Currently there is no way of tuning the
  parameters for these checks. Please tell me if you are having problems
  with the settings for your extract.
- "Historic development" report showing numbers of unique keys, tags, and
  relation types over time. This report uses data accumulated over time in
  the taginfo-history.db database by each taginfo update run. This data
  wasn't used until now.

To ease the transition, the "Similar keys" report will show a warning if
the data needed for the report is not available. After the next update run
it should just work. The "Similar" tab will only work once the config
setting 'user_interface.key_page.show_tab_similar' is set to 'true'. By
default it is 'false'.

To update to this version:
- Update taginfo from github.
- Call 'make' in the 'tagstats' directory. There will be an additional binary
  called 'similarity'. Set 'sources.db.bindir' to wherever that binary is.
  The default will just access that 'tagstats' directory, but you can change
  that if you prefer to have the binary somewhere else.
- Run the update as usual.
- If the update ran through properly, there are two new tables in the
  'taginfo-db.db' called 'similar_keys' and 'similar_keys_common_rare'.
- Set config 'user_interface.key_page.show_tab_similar' to 'true'.
- Restart server.

The main taginfo site should have the updates tomorrow. You can check the
updates at the test site:
http://mercator.openstreetmap.de/keys/cuisine#similar
http://mercator.openstreetmap.de/reports/similar_keys
http://mercator.openstreetmap.de/reports/historic_development

Jochen
-- 
Jochen Topf  jochen at remote.org  http://www.jochentopf.com/  +49-173-7019282