update documentation for new wikipedia data

docs/admin/Import-and-Update.md

@@ -33,7 +33,7 @@ the directory exists. There should be at least 40GB of free space.
 
 ## Downloading additional data
 
-### Wikipedia rankings
+### Wikipedia/Wikidata rankings
 
 Wikipedia can be used as an optional auxiliary data source to help indicate
 the importance of OSM features. Nominatim will work without this information
@@ -41,15 +41,14 @@ but it will improve the quality of the results if this is installed.
 This data is available as a binary download:
 
     cd $NOMINATIM_SOURCE_DIR/data
-    wget https://www.nominatim.org/data/wikipedia_article.sql.bin
-    wget https://www.nominatim.org/data/wikipedia_redirect.sql.bin
+    wget https://www.nominatim.org/data/wikimedia_importance.sql.gz
 
-Combined the 2 files are around 1.5GB and add around 30GB to the install
+The file is about 1GB and it adds around 10GB to the install
 size of Nominatim. They also increase the install time by an hour or so.
 
-*NOTE:* you'll need to download the Wikipedia rankings before performing
-the initial import of the data if you want the rankings applied to the
-loaded data.
+*NOTE:* if you forgot to download the wikipedia rankings, you can also add
+them after the import by running `./utils/setup.php --import-wikipedia-articles`
+and then `./utils/update.php --recompute-importance`.
 
 ### Great Britain, USA postcodes
 

docs/admin/Migration.md

@@ -6,6 +6,21 @@ to newer versions of Nominatim.
 SQL statements should be executed from the PostgreSQL commandline. Execute
 `psql nominatim` to enter command line mode.
 
+## 3.4.0 -> master
+
+### New Wikipedia/Wikidata importance tables
+
+The `wikipedia_*` tables have a new format that also includes references to
+Wikidata. You need to update the computation functions and the tables as
+follows:
+
+  * download the new Wikipedia tables as described in the import section
+  * reimport the tables: `./utils/setup.php --import-wikipedia-articles`
+  * update the functions: `./utils/setup.php --create-functions --enable-diff-updates`
+  * compute importance: `./utils/update.php --recompute-importance`
+
+The last step takes about 10 hours on the full planet.
+
 ## 3.3.0 -> 3.4.0
 
 ### Reorganisation of location_area_country table