WOF in a Box (part 3) This is a blog post by thisisaaronland that was published on Feb 20, 2018 and tagged spelunker, sqlite, whosonfirst and wof-in-a-box
The Who’s On First Spelunker lives again! Its new home is:
Any old Spelunker URLs should continue to work as-is once you update the root, replacing
spelunker.whosonfirst.org. For example, the URL for the Who’s On First record for
Tokyo used to be:
And now it is:
The rest of this blog post is divided up in to two parts, one nerdier than the next. The first section describes a couple of mechanical changes we made to speed up rebuilding the Spelunker (“part 3” of WOF in a Box).
In my mind everything up to and including the Spelunker is “near-term”, the API and the spatial services are “medium-term” and the editorial stuff is “longer-term”. It’s not ideal but it seems the most realistic given whatever world of new everyone involved in the project will be negotiating during the coming year.
The second section builds on the first and discusses what we’ve been up to post-Mapzen and where things are going next. This is the “medium-term” work outlined in the blog post that followed the announcement that Mapzen was shutting down.
It’s pretty technical so if that’s not your jam you can skip it all in good conscience and head over the to the Spelunker and start spelunking away again.
The Spelunker was rebuilt on a bare Ubuntu 16.04 Linux server, following Dan’s WOF in a Box instructions and everything worked without a hitch. Along the way, I made some updates to the “fetching and indexing data” pieces specifically to make things faster and easier for people who just want to work with the data as-is and don’t need to make updates.
These updates actually introduced some “hitches” in Dan’s guide but with Gary Gale ’s help we were able to make short work of those bugs and everything should work as advertised again…
Historically all the Who’s On First tools have been designed to work with the raw (plain-text GeoJSON) data contained in the GitHub repositories. It’s important that there always be tooling to work with the raw “at rest” data but it can be unnecessarily fiddly for a lot of people.
We’ve been doing a lot of work recently to distribute Who’s On First data as SQLite databases. SQLite databases have the advantage of being self-contained with widespread support in a variety of tools and programming languages. They don’t currently include alternate geometry WOF records but those aren’t necessary for most of the things that people want to do with WOF related tools.
The first tool that we wrote is a simple command-line tool to fetch all of the
databases defined in an
inventory.json file. These
inventory.json files are still a work in progress and currently only
published for SQLite databases. As we chip away at the remaining work to
generate other Who’s On First distributions the plan is to adopt and adapt the
inventory files accordingly. More on that below.
Here’s how to the wof-dist-fetch tool works. In this example we’re going to
ask the tool to fetch every database listed in the inventory file, and
store them in a folder called
> wof-dist-fetch -inventory https://dist.whosonfirst.org/sqlite/inventory.json -dest /usr/local/data ...time passes... > ls -d /usr/local/data/whosonfirst-data* /usr/local/data/whosonfirst-data-constituency-ca.db /usr/local/data/whosonfirst-data-constituency-ca-latest.db /usr/local/data/whosonfirst-data-constituency-us-latest.db ... /usr/local/data/whosonfirst-data-venue-us-wy-latest.db /usr/local/data/whosonfirst-data-venue-uy-latest.db /usr/local/data/whosonfirst-data-venue-za-latest.db
You can also filter specific databases by passing one or more
-exclude flags. For example if we only wanted to download postal code
databases we would do this:
> wof-dist-fetch -inventory https://dist.whosonfirst.org/sqlite/inventory.json -dest /usr/local/data -include 'whosonfirst-data-postalcode-*-latest.db'
wof-dist-fetch tool replaces the steps described in the Download some
data section of Dan’s post. It will
still take a while to download all the SQLite databases but they are generally
smaller and easier to work with than the Git repositories and don’t require
setting up additional tools like Git LFS.
wof-dist-fetch tool is part of the go-whosonfirst-dist package which will also be used
to generate those SQLite files and other distributions. The package contains different tools to fetch and build distributions but the latter are still being actively developed so you probably shouldn’t try using those yet, unless you are
The second tool is actually just an update to one of the very first tools we ever wrote. The wof-es-index tool is used to crawl a directory full of Who’s On First GeoJSON data files and index them in the Who’s On First Spelunker Elasticsearch index. It has been updated to also read and index WOF data stored in the SQLite databases we’re generating. In Dan’s original blog post you would index the Spelunker like this:
> cd /usr/local/data/whosonfirst-data > wof-es-index -s . --index=spelunker -b
And now you can do this:
> wof-es-index -b -m sqlite /usr/local/data/whosonfirst-data-*-latest.db
-s(ource) flag has been deprecated and replaced with the
which can index a number of different data sources: Git repositories, SQLite
databases, one or more GeoJSON files and so on. It is also no longer necessary
to pass the
-i(ndex) flag since it defaults to “spelunker” now. The trusty
-b(ulk) flags remains unchanged for speeding up indexing.
So, it’s only a pair of small tweaks to Dan’s instructions but hopefully they are useful ones.
There’s been a lot of work on the SQLite databases leading up to those tweaks including adding full-text and spatial indexing as well as refactoring the code in to re-usable components so that it can be used for other kinds of data, specifically Who’s On First brands and Markdown files.
In all there are three distinct packages, two of them for Who’s On First features and brands and another for generic Markdown files, and a fourth shared by all the others:
There is even an experimental
go-whosonfirst-sqlite package for working with Privatezen databases but it’s still too soon to discuss that yet.
The support for Markdown files is not as much of a non-sequitur as it might seem. Part of living in a post-Mapzen world has involved moving all the Who’s On First blog posts (from the Mapzen website) over here. That’s meant writing our own suite of tools to render the Jekyll-flavoured Markdown files that we’ve always used for blog posts.
Last summer we launched “version 2” of the Who’s On First website, the result of Scott Dombrowski ’s internship with Mapzen. It has been a huge UI and UX improvement and helped corral all the many different sources of documentation in to one place.
On the other hand the website still requires more work than it should in order to update or add new pages so “version 3” will essentially be Markdown files written by hand or derived from machine readable data that will be rendered as HTML with the same tools that I wrote for the blog.
The value of being able to index Markdown files in SQLite is that we are now able to do full-text search, first for the blog but ultimately for all the WOF related documentation, once the “version 3” work is completed:
> ./bin/wof-sqlite-query-markdown -dsn test.db montreal 15:49:12.499695 [wof-sqlite-query-markdown] STATUS montreal - /blog/2015/08/18/who-s-on-first/ 15:49:12.499856 [wof-sqlite-query-markdown] STATUS montreal - /blog/2017/04/04/whosonfirst-api/ 15:49:12.499906 [wof-sqlite-query-markdown] STATUS montreal - /blog/2017/10/17/whosonfirst-nacis-2017/ 15:49:12.499936 [wof-sqlite-query-markdown] STATUS montreal - /blog/2017/12/22/neighbourhood-updates-three/ 15:49:12.500024 [wof-sqlite-query-markdown] STATUS montreal - /blog/2015/08/18/who-s-on-first/
Careful readers will note that it’s still not possible to search the weblog on the weblog itself. It will become possible, I promise, just not today…
We used the blog as a testing and proving ground for how full-text search should work and then applied those lessons to the tools we use to index and query brands:
> ./bin/wof-sqlite-query-brands -dsn test.db 'car* bank' 17:23:40.459620 [wof-sqlite-query-brands] STATUS car* bank - 1125154403 Carolina First Bank 17:23:40.459746 [wof-sqlite-query-brands] STATUS car* bank - 1125153083 Central Carolina Bank
And then finally for actual Who’s On First documents:
> ./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
We’ve also added the ability to index and query Who’s On First geometries for people who have the Spatialite extension installed on their computers.
> ./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
Now that we’ve sorted out how to index and query spatial properties in the
SQLite databases we’ve also begun work on a
spatialite branch of the Who’s On First point-in-polygon
is to speed up indexing time and memory usage (and maybe even query time) by teaching
the code to use the newer SQLite databases instead of an in-memory
RTree. Our hope is people can simply download one or
more of the SQLite databases using the
wof-dist-fetch tool described above,
point the PIP server at those databases and having a working services in a
matter of minutes.
The other hope is that these SQLite databases can be integrated with existing Who’s On First applications, like the Spelunker or the API, to provide an abbreviated set of features – a sort of “Who’s On First Lite” – for people who aren’t in a position to set up more complicated databases like Elasticsearch.
There’s still some heavy-lifting and hoop-jumping to complete before any of this is possible but that is the goal.
There are three reasons we’ve been spending so much time on the SQLite databases:
They are super cool and super useful in their own right.
Life has been mostly interupt-driven since the Mapzen shutdown and hasn’t lent itself to more concentrated work.
I have a hunch that we can use these SQLite databases to more effeciently update all the other tools and services whether it’s the Spelunker, the API, the raw data.whosonfirst.org files or other bulk distributions that people might want to download.
But that means building those SQLite databases first and doing so in a timely and automated fashion when changes are pushed to the actual Who’s On First data. That’s where we’re at today: Working through those details and figuring out how to improve on the bubble-gum and duct tape solutions that got us this far.
The goal for the next phase of work is to set up a reliable workflow for
generating both bundles and
SQLite databases for each of the
whosonfirst-data repositories, along with
a standardized “inventory” file for both formats that can be consumed by the
wof-dist-fetch tool, and then to use those distributions to update the
Spelunker and the
If you’re curious you can follow along in the sqlite and bundles branches of the go-whosonfirst-dist package.
Once that’s working then we’ll turn our attention to spinning up the Who’s On First API again. No one is working on this “40 hours a week” anymore so it may take a bit longer than we’d like but hopefully not too much longer.
In the meantime, the Spelunker is back!