Simon Willison’s Weblog

OpenStreetMap embed URL. I just found out OpenStreetMap have a "share" button which produces HTML for an iframe targetting https://www.openstreetmap.org/export/embed.html, making it easy to drop an OpenStreetMap map onto any web page that allows iframes.

As far as I can tell the supported parameters are:

• bbox= then min longitude, min latitude, max longitude, max latitude
• marker= optional latitude, longitude coordinate for a marker (only a single marker is supported)
• layer=mapnik - other values I've found that work are cyclosm, cyclemap, transportmap and hot (for humanitarian)

Here's HTML for embedding this on a page using a sandboxed iframe - the allow-scripts is necessary for the map to display.

<iframe
  sandbox="allow-scripts"
  style="border: none; width: 100%; height: 20em;"
  src="https://www.openstreetmap.org/export/embed.html?bbox=-122.613%2C37.431%2C-122.382%2C37.559&amp;layer=mapnik&amp;marker=37.495%2C-122.497"
></iframe>

Thanks to this post I learned that iframes are rendered correctly in NetNewsWire, NewsExplorer, NewsBlur and Feedly on Android.

# 25th November 2024, 7:29 pm / sandboxing, iframes, gis, openstreetmap

OpenStreetMap vector tiles demo (via) Long-time OpenStreetMap developer Paul Norman has been working on adding vector tile support to OpenStreetMap for quite a while. Paul recently announced that vector.openstreetmap.org is now serving vector tiles (in Mapbox Vector Tiles (MVT) format) - here's his interactive demo for seeing what they look like.

# 19th November 2024, 11:39 pm / gis, openstreetmap, mapping

OpenFreeMap (via) New free map tile hosting service from Zsolt Ero:

OpenFreeMap lets you display custom maps on your website and apps for free. […] Using our public instance is completely free: there are no limits on the number of map views or requests. There’s no registration, no user database, no API keys, and no cookies. We aim to cover the running costs of our public instance through donations.

The site serves static vector tiles that work with MapLibre GL. It deliberately doesn’t offer any other services such as search or routing.

From the project README looks like it’s hosted on two Hetzner machines. I don’t think the public server is behind a CDN.

Part of the trick to serving the tiles efficiently is the way it takes advantage of Btrfs:

Production-quality hosting of 300 million tiny files is hard. The average file size is just 450 byte. Dozens of tile servers have been written to tackle this problem, but they all have their limitations.

The original idea of this project is to avoid using tile servers altogether. Instead, the tiles are directly served from Btrfs partition images + hard links using an optimised nginx config.

The self-hosting guide describes the scripts that are provided for downloading their pre-built tiles (needing a fresh Ubuntu server with 300GB of SSD and 4GB of RAM) or building the tiles yourself using Planetiler (needs 500GB of disk and 64GB of RAM).

Getting started is delightfully straightforward:

const map = new maplibregl.Map({
  style: 'https://tiles.openfreemap.org/styles/liberty',
  center: [13.388, 52.517],
  zoom: 9.5,
  container: 'map',
})

I got Claude to help build this demo showing a thousand random markers dotted around San Francisco. The 3D tiles even include building shapes!

Zsolt built OpenFreeMap based on his experience running MapHub over the last 9 years. Here’s a 2018 interview about that project.

It’s pretty incredible that the OpenStreetMap and open geospatial stack has evolved to the point now where it’s economically feasible for an individual to offer a service like this. I hope this turns out to be sustainable. Hetzner charge just €1 per TB for bandwidth (S3 can cost $90/TB) which should help a lot.

# 28th September 2024, 9:41 pm / maps, ai-assisted-programming, geospatial, openstreetmap

Optimizing Large-Scale OpenStreetMap Data with SQLite (via) JT Archie describes his project to take 9GB of compressed OpenStreetMap protobufs data for the whole of the United States and load it into a queryable SQLite database.

OSM tags are key/value pairs. The trick used here for FTS-accelerated tag queries is really neat: build a SQLite FTS table containing the key/value pairs as space concatenated text, then run queries that look like this:

SELECT
    id
FROM
    entries e
    JOIN search s ON s.rowid = e.id
WHERE
    -- use FTS index to find subset of possible results
    search MATCH 'amenity cafe'
    -- use the subset to find exact matches
    AND tags->>'amenity' = 'cafe';

JT ended up building a custom SQLite Go extension, SQLiteZSTD, to further accelerate things by supporting queries against read-only zstd compresses SQLite files. Apparently zstd has a feature that allows "compressed data to be stored so that subranges of the data can be efficiently decompressed without requiring the entire document to be decompressed", which works well with SQLite's page format.

# 2nd July 2024, 2:33 pm / zstd, go, openstreetmap, sqlite

How The Post is replacing Mapbox with open source solutions (via) Kevin Schaul describes the Washington Post’s emerging open source GIS stack: OpenMapTiles, Maputnik, PMTiles and Maplibre-gl-js.

# 17th February 2023, 6:45 pm / maps, washington-post, openstreetmap, opensearch

Announcing Daylight Map Distribution. Mike Migurski announces a new distribution of OpenStreetMap: a 42GB dump of the version of the data used by Facebook, carefully moderated to minimize the chance of incorrect or maliciously offensive edits. Lots of constructive conversation in the comments about the best way for Facebook to make their moderation decisions more available to the OSM community.

# 12th March 2020, 11:44 am / facebook, openstreetmap, michal-migurski

Statistical NLP on OpenStreetMap. libpostal is ferociously clever: it’s a library for parsing and understanding worldwide addresses, built on top of a machine learning model trained on millions of addresses from OpenStreetMap. Al Barrentine describes how it works in this fascinating and detailed essay.

# 8th January 2018, 7:33 pm / machine-learning, nlp, openstreetmap

simonepri/geo-maps. Neat project which publishes GeoJSON maps of the world automatically derived from OpenStreetMap. Three variants are available: country political maritime boundaries, country political coastline boundaries and a general outline of the world’s land territories.

# 21st November 2017, 4:06 pm / geojson, gis, openstreetmap

We Need to Stop Google’s Exploitation of Open Communities. Mikel Maron from OpenStreetMap is justifiably angry about Google MapMaker, which copies OpenStreetMap’s model of crowdsourcing geographic data (even copying the OSM idea of Mapping Parties) but keeps the data under a much more restrictive license, and uses the Google brand to market itself to African governments.

# 22nd April 2011, 10 am / google, mapmaker, openstreetmap, recovered

Polymaps. Absurdly classy: “a JavaScript library for image- and vector-tiled maps using SVG”. It can pull in image tiles from sources such as OpenStreetMap, then overlay SVG paths specified using GeoJSON. The demos make use of GeoJSON tiles for US states and counties hosted on AppEngine. The library is developed by Stamen and SimpleGeo, and released under a BSD license. SVG support in the browser is required.

# 20th August 2010, 6:46 pm / appengine, geojson, javascript, mapping, polymaps, simplegeo, svg, recovered, stamen-design, openstreetmap

MapOSMatic. Clever service built on top of OpenStreetMap, which renders double sided city maps with a map and grid on one size and an A-Z street name index on the other. Runs on top of Mapnik, PostGIS and Cairo, with a few thousand additional lines of Python and Django.

# 11th July 2010, 12:15 pm / cairo, django, maposmatic, mapping, openstreetmap, postgis, postgresql, python, recovered

getlatlon.com commit dae961a... I’ve finally added an OpenStreetMap tab to getlatlon.com—here’s the diff, it turns out adding a custom OpenStreetMap layer to an existing Google Maps application only takes a few lines of boilerplate code.

# 10th July 2010, 12:22 pm / getlatlon, google-maps, javascript, openstreetmap, projects, recovered

Why Google MapMaker is not Open. Non-commercial use only, strict attribution requirements and you aren’t allowed to use the data for services that might compete with Google. This is why I’m disappointed every time I see Google encouraging people to contribute to Map Make, especially in the developing world—if those people contributed to OpenStreetMap instead they would be building something far more valuable for their community.

# 16th March 2010, 10:41 am / openstreetmap, google, mapmaker, mikel-maron

On walking into a disaster zone. Schuyler Erle: “The World Bank was looking for technical GIS professionals, ideally French-speaking, to go and advise the government [...] I can sort of speak French. Sure, why not?”

# 10th February 2010, 3:45 pm / schuylererle, haiti, openstreetmap, worldbank, gis

OSM the default map in Haiti. A search and rescue team member in Haiti sends word that digital maps constructed by the OpenStreetMap community are spreading by word of mouth and being loaded on to GPS units on the ground.

# 25th January 2010, 9:26 pm / openstreetmap, haiti, inspiring, mapping, gps

The View from Above. Andy Allan’s notes on three different projects that aerial imagery with OpenStreetMap. Andy and friends hired a small plane and took their own aerial photographs of Stratford-upon-Avon as a demo for a GIS conference. Aid agencies in the Philippines benefitted from OSM and a donation of high quality satellite imagery. Rural Georgia now has hiqh quality images from 2007 thanks to the Department of Agriculture.

# 11th December 2009, 9:32 am / openstreetmap, aerialimagery, satellites, mapping, andy-allan

Temporary Mapping: Solar Decathlon. The OpenStreetMap default renderer supports start_date and end_date tags, meaning you can map temporary installations (in this case the 2009 Solar Decathlon on the DC National Mall) and have them automatically appear and disappear at the correct times.

# 13th October 2009, 3:18 pm / openstreetmap, andrew-turner, solardecathlon, mapping, tags

OSM static map api. A very welcome addition to the OpenStreetMap world (with plenty of options for overlaying points, polygons etc) slightly marred by the size and relative ugliness of the OpenStreetMap watermark.

# 12th October 2009, 1:37 pm / openstreetmap, mapping, apis, staticmaps, watermarks

OpenStreetMap Rendering Database. Amazon have added an OpenStreetMap snapshot as a public data set, thanks to some smart prompting by Jeremy Dunck.

# 10th October 2009, 1:05 pm / amazon, ec2, s3, publicdatasets, openstreetmap, mapping, jeremy-dunck

openstreetmap genuine advantage. The OpenStreetMap data model (points, ways and relations, all allowing arbitrary key/value tags) is a real thing of beauty—simple to understand but almost infinitely extensible. Mike Migurski’s latest project adds PGP signing to OpenStreetMap, allowing organisations (such as local government) to add a signature to a way (a sequence of points) and a subset of its tags, then write that signature in to a new tag on the object.

# 29th September 2009, 9:49 am / michal-migurski, openstreetmap, pgp, cryptography, mapping, gis

“That’s maybe a bit too dorky, even for us.”. Astonishingly exciting: Flickr now have machine tag support for OpenStreetMap—tag a photo with osm:way=WAY_ID and Flickr will figure out what OSM feature you are talking about and link to it with a human readable description.

# 28th September 2009, 10:39 pm / openstreetmap, flickr, machinetags, photography

OpenStreetMap: QuadTiles. Fascinating explanation of a proposal for replacing lat, lon pairs in the OpenStreetMap database with a QuadTile-based addressing system.

# 10th September 2009, 3:54 pm / quadtiles, openstreetmap, algorithms, gis

Tile Drawer (via) The most inspired use of EC2 I’ve seen yet: center a map on an area, pick a Cascadenik stylesheet URL (or write and link to your own) and Tile Drawer gives you an Amazon EC2 AMI and a short JSON snippet. Launch the AMI with the JSON as the “user data” parameter and you get your own OpenStreetMap tile rendering server, which self-configures on startup and starts rendering and serving tiles using your custom design.

# 26th August 2009, 9:32 am / openstreetmap, ec2, amazon, michal-migurski, cascadenik, mapnik, cloud-computing, json, userdata, mapping

Best of OpenStreetMap (via) I keep on telling people OpenStreetMap is this year’s Wikipedia—at its best, it beats commercially available maps. This “best of” site highlights the areas where OSM really shines (the yellow stars)—the German mapping community in particular have produced some outstanding cartography.

# 13th August 2009, 12:30 pm / openstreetmap, wikipedia, mapping, maps, cartography

Augmenting photos—with OSM! “You climbed up a mountain and took a photo ... but it’s 2009! Why doesn’t it have all kind of magic over the top of it.”—Marmota matches your landscape photos to height field data, then overlays data from OpenStreetMap mapped to the contours of the photograph.

# 9th June 2009, 11:34 am / photography, gps, magic, marmota, openstreetmap, steve-coast