index

go-whosonfirst-sqlite-features-index

Go package for indexing Who's On First features in SQLite databases.

Tools

wof-sqlite-index-features

  -all
    	Index all tables (except the 'search' and 'geometries' tables which you need to specify explicitly)
  -ancestors
    	Index the 'ancestors' tables
  -concordances
    	Index the 'concordances' tables
  -driver string
    	 (default "sqlite3")
  -dsn string
    	 (default ":memory:")
  -geojson
    	Index the 'geojson' table
  -geometries
    	Index the 'geometries' table (requires that libspatialite already be installed)
  -index-alt-files
    	Index alt geometries
  -index-belongs-to
    	Index the records listed in a feature's 'wof:belongsto' array. Alt files for 'wof:belongsto' are not indexed at this time.
  -index-belongs-to-uri string
    	A valid go-reader.Reader URI from which to read data for a 'wof:belongsto' candidate.
  -live-hard-die-fast
    	Enable various performance-related pragmas at the expense of possible (unlikely) database corruption (default true)
  -mode string
    	The mode to use importing data. Valid modes are: directory,featurecollection,file,filelist,geojsonl,metafile,repo,sqlite. (default "files")
  -names
    	Index the 'names' table
  -optimize
    	Attempt to optimize the database before closing connection (default true)
  -processes int
    	The number of concurrent processes to index data with (default 8)
  -search
    	Index the 'search' table (using SQLite FTS4 full-text indexer)
  -spr
    	Index the 'spr' table
  -strict-alt-files
    	Be strict when indexing alt geometries (default true)
  -timings
    	Display timings during and after indexing

For example:

./bin/wof-sqlite-index-features -live-hard-die-fast -dsn microhoods.db -all -mode meta /usr/local/data/whosonfirst-data/meta/wof-microhood-latest.csv

See the way we're passing a -live-hard-die-fast flag? That is to enable a number of performace-related PRAGMA commands (described here and here) without which database index can be prohibitive and time-consuming. These is a small but unlikely chance of database corruptions when this flag is enabled.

Also note that the -live-hard-die-fast flag will cause the PAGE_SIZE and CACHE_SIZE PRAGMAs to be set to 4096 and 1000000 respectively so the eventual cache size will require 4GB of memory. This is probably fine on most systems where you'll be indexing data but I am open to the idea that we may need to revisit those numbers or at least make them configurable.

You can also use wof-sqlite-index-features in combination with the go-whosonfirst-api wof-api tool and populate your SQLite database by piping API results on STDIN. For example, here's how you might index all the neighbourhoods in Montreal:

/usr/local/bin/wof-api -param method=whosonfirst.places.getDescendants -param id=101736545 \
-param placetype=neighbourhood -param api_key=mapzen-xxxxxx -geojson-ls | \
/usr/local/bin/wof-sqlite-index-features -dsn neighbourhoods.db -all -mode geojson-ls STDIN

Or creating databases for all the Who's On First repos:

#!/bin/sh

for REPO in $@
do

    if [ ! -d ${REPO}/data ]
    then
	echo "${REPO} has no data directory"
	continue
    fi
    
    FNAME=`basename ${REPO}`
    echo "make db for ${FNAME}"

    if [ -f "/usr/local/data/whosonfirst-sqlite/${FNAME}.db" ]
    then
	rm /usr/local/data/whosonfirst-sqlite/${FNAME}.db
    fi

    ./bin/wof-sqlite-index-features -timings -live-hard-die-fast -all -dsn /usr/local/data/whosonfirst-sqlite/${FNAME}-latest.db -mode repo ${REPO} 

done

wof-sqlite-query-features

Query a search-enabled SQLite database by name(s). Results are output as CSV encoded rows containing id and (wof:)name properties.

This assumes you have created the database using the wof-sqlite-index-features tool with the -search paramter.

./bin/wof-sqlite-query-features -h
Usage of ./bin/wof-sqlite-query-features:
  -column string
    	The 'names_*' column to query against. Valid columns are: names_all, names_preferred, names_variant, names_colloquial. (default "names_all")
  -driver string
    	 (default "sqlite3")
  -dsn string
    	 (default ":memory:")
  -is-ceased string
    	A comma-separated list of valid existential flags (-1,0,1) to filter results according to whether or not they have been marked as ceased. Multiple flags are evaluated as a nested 'OR' query.
  -is-current string
    	A comma-separated list of valid existential flags (-1,0,1) to filter results according to their 'mz:is_current' property. Multiple flags are evaluated as a nested 'OR' query.
  -is-deprecated string
    	A comma-separated list of valid existential flags (-1,0,1) to filter results according to whether or not they have been marked as deprecated. Multiple flags are evaluated as a nested 'OR' query.
  -is-superseded string
    	A comma-separated list of valid existential flags (-1,0,1) to filter results according to whether or not they have been marked as superseded. Multiple flags are evaluated as a nested 'OR' query.
  -output string
    	A valid path to write (CSV) results to. If empty results are written to STDOUT.
  -table string
    	The name of the SQLite table to query against. (default "search")

For example:

./bin/wof-sqlite-query-features -dsn test2.db JFK
102534365,John F Kennedy Int'l Airport

./bin/wof-sqlite-query-features -dsn test2.db -column names_colloquial Paris
85922583,San Francisco
102027181,Shanghai
102030585,Kolkata
101751929,Tromsø

Full-text search is supported using SQLite's FTS4 indexer. In order to index the search table you must explicitly pass the -search flag to the wof-sqlite-index-features command. It is not included when you set the -all flag (which should probably be renamed to be -common but that's not the case today...) because it increases the overall indexing time by a non-trivial amount.

Spatial indexes

Yes, if you have the Spatialite extension installed and have indexed the geometries table. For example:

> ./bin/wof-sqlite-index-features -timings -live-hard-die-fast -spr -geometries -driver spatialite -mode repo -dsn test.db /usr/local/data/whosonfirst-data-constituency-ca/
10:09:46.534281 [wof-sqlite-index-features] STATUS time to index geometries (87) : 21.251828704s
10:09:46.534379 [wof-sqlite-index-features] STATUS time to index spr (87) : 3.206930799s
10:09:46.534385 [wof-sqlite-index-features] STATUS time to index all (87) : 24.48004637s

> sqlite3 test.db
SQLite version 3.21.0 2017-10-24 18:55:49
Enter ".help" for usage hints.

sqlite> SELECT load_extension('mod_spatialite.dylib');
sqlite> SELECT s.id, s.name FROM spr s, geometries g WHERE ST_Intersects(g.geom, GeomFromText('POINT(-122.229137 49.450129)', 4326)) AND g.id = s.id;
1108962831|Maple Ridge-Pitt Meadows

Or:

> spatialite whosonfirst-data-latest.db
SpatiaLite version ..: 4.1.1	Supported Extensions:
...spatialite chatter goes here...
SQLite version 3.8.2 2013-12-06 14:53:30
Enter ".help" for instructions
Enter SQL statements terminated with a ";

spatialite> SELECT s.id, s.name FROM spr AS s, geometries AS g1, geometries AS g2 WHERE g1.id =  85834637 AND s.placetype = 'neighbourhood' AND g2.id = s.id AND ST_Touches(g1.geom, g2.geom) AND g2.ROWID IN (SELECT ROWID FROM SpatialIndex WHERE f_table_name = 'geometries' AND search_frame=g2.geom);
102112179|La Lengua
1108831803|Showplace Square

spatialite> SELECT s.id, s.name FROM spr AS s, geometries AS g1, geometries AS g2 WHERE g1.id != g2.id AND g1.id =  85865959 AND s.placetype = 'neighbourhood' AND s.is_current=1 AND g2.id = s.id AND (ST_Touches(g1.geom, g2.geom) OR ST_Intersects(g1.geom, g2.geom)) AND g2.ROWID IN (SELECT ROWID FROM SpatialIndex WHERE f_table_name = 'geometries' AND search_frame=g2.geom);
1108831807|Fairmount
85814471|Diamond Heights
85869221|Eureka Valley

SELECT s.id, s.name, s.is_current FROM spr AS s, geometries AS g1, geometries AS g2 WHERE g1.id != g2.id AND g1.id =  102061079 AND s.placetype = 'neighbourhood' AND g2.id = s.id AND (ST_Touches(g1.geom, g2.geom) OR ST_Intersects(g1.geom, g2.geom)) AND g2.ROWID IN (SELECT ROWID FROM SpatialIndex WHERE f_table_name = 'geometries' AND search_frame=g2.geom);
85892915|BoCoCa|0
85869125|Boerum Hill|1
420782915|Carroll Gardens|1
85865587|Gowanus|1

Remember: When indexing geometries you will need to explcitly pass both the -geometries and -driver spatialite flags, even if you are already passing in the -all flag. This is so -all will continue to work as expected for people who don't have Spatialite installed on their computer.

Indexing

Indexing time will vary depending on the specifics of your hardware (available RAM, CPU, disk I/O) but as a rule building indexes with the geometries table will take longer, and create a larger database, than doing so without. For example indexing the whosonfirst-data repository with spatial indexes:

> ./bin/wof-sqlite-index-features -all -driver spatialite -geometries -dsn /usr/local/data/dist/sqlite/whosonfirst-data-latest.db -live-hard-die-fast -timings -mode repo /usr/local/data/whosonfirst-data
...time passes...
06:12:51.274132 [wof-sqlite-index-features] STATUS time to index geojson (951541) : 13m41.994217581s
06:12:51.274158 [wof-sqlite-index-features] STATUS time to index spr (951541) : 13m0.21007633s
06:12:51.274173 [wof-sqlite-index-features] STATUS time to index names (951541) : 17m50.759093941s
06:12:51.274178 [wof-sqlite-index-features] STATUS time to index ancestors (951541) : 3m37.431723948s
06:12:51.274182 [wof-sqlite-index-features] STATUS time to index concordances (951541) : 2m36.737857568s
06:12:51.274187 [wof-sqlite-index-features] STATUS time to index geometries (951541) : 43m48.39054903s
06:12:51.274192 [wof-sqlite-index-features] STATUS time to index all (951541) : 4h41m45.492361401s

> du -h /usr/local/data/dist/sqlite/whosonfirst-data-latest.db
15G     /usr/local/data/dist/sqlite/whosonfirst-data-latest.db

And without:

> ./bin/wof-sqlite-index-features -all -dsn /usr/local/data/dist/sqlite/whosonfirst-data-latest-nospatial.db -live-hard-die-fast -timings -mode repo /usr/local/data/whosonfirst-data
...time passes...
10:06:13.226187 [wof-sqlite-index-features] STATUS time to index names (951541) : 12m32.359733539s
10:06:13.226206 [wof-sqlite-index-features] STATUS time to index ancestors (951541) : 3m27.294843778s
10:06:13.226212 [wof-sqlite-index-features] STATUS time to index concordances (951541) : 2m5.947968206s
10:06:13.226220 [wof-sqlite-index-features] STATUS time to index geojson (951541) : 10m11.355455209s
10:06:13.226226 [wof-sqlite-index-features] STATUS time to index spr (951541) : 11m32.687081163s
10:06:13.226233 [wof-sqlite-index-features] STATUS time to index all (951541) : 3h43m20.687783762s

> du -h /usr/local/data/dist/sqlite/whosonfirst-data-latest-nospatial.db 
12G     /usr/local/data/dist/sqlite/whosonfirst-data-latest-nospatial.db

As of this writing individual tables are indexed atomically. There may be some improvements to be made indexing tables in separate Go routines but my hunch is this will make SQLite sad and cause a lot of table lock errors. I don't need to be right about that, though...

Dependencies and relationships

These are documented in the Dependencies and relationships section of the go-whosonfirst-sqlite package.

See also

• https://github.com/whosonfirst/go-whosonfirst-sqlite
• https://github.com/whosonfirst/go-whosonfirst-sqlite-features