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Our OSM Inspector web site is an important part of many a mapper’s toolbox. It has a series of, daily updated, debug views on OSM data, highlighting potential problems from invalid multipolygons over strange tagging or faulty geometries to missing address data.

The OSM Inspector, or OSMI for short, has several thematic views (like “geometry”, “tagging”, “boundaries”), each of which again supports a number of individually selectable layers that highlight a specific kind of problem. OSMI displays its results over an OSM base map, and you can select individual bug reports and get more information about them, or even download a list of errors for further processing. There’s extensive documentation on the OpenStreetMap Wiki.

Worldwide Routing View

While most views have always shown data computed in-house at Geofabrik, one of our views, the routing view, presents data that comes from an algorithm developed by Pascal Neis of OpenRouteService fame, and is sponsored by Skobbler. The routing view attempts to highlight obstacles to routing – mostly roads that are not connected when they should be, but also duplicate roads that may lead to strange routing results.

We do not have a sponsor for running this routing view world-wide on a daily basis right now, but we have run it once for the non-Europe part of the planet, and you can try it out here:

OSMI Routing View Non-EU

We’ll try to update this once a week or so. (The normal, sponsored routing view for Europe with daily updates is here.)

In all, OSMI has data collected by three different toolchains; one of them works globally and feeds e.g. the tagging, multipolygon, and general geometry debug views; the other two, including the routing view toolchain, currently do Europe only and would require re-writing or more hardware to cope with the whole planet.

Potlatch

It has always been possible to access OSMI views through WMS for use in other applications, especially as a background layer in editors. Users of the popular Potlatch editor were however unable to make use of this as Potlatch does not support WMS backgrounds. We have therefore configured OSMI to serve tiles as well. (We’re using the excellent open source MapProxy for that.)

If you are using Potlatch, you can now add any or all of the following background layers:

  • Geometry View: http://tools.geofabrik.de/osmi/tiles/geometry/$z/$x/$y.png
  • Places View: http://tools.geofabrik.de/osmi/tiles/places/$z/$x/$y.png
  • Tagging View: http://tools.geofabrik.de/osmi/tiles/tagging/$z/$x/$y.png
  • Highways View: http://tools.geofabrik.de/osmi/tiles/highways/$z/$x/$y.png
  • Multipolygon View: http://tools.geofabrik.de/osmi/tiles/multipolygon/$z/$x/$y.png
  • Address View (*): http://tools.geofabrik.de/osmi/tiles/addresses/$z/$x/$y.png
  • Boundaries View (*): http://tools.geofabrik.de/osmi/tiles/boundaries/$z/$x/$y.png
  • Water View (*): http://tools.geofabrik.de/osmi/tiles/water/$z/$x/$y.png
  • Routing View (*): http://tools.geofabrik.de/osmi/tiles/routing/$z/$x/$y.png
  • Routing View (non-Europe): http://tools.geofabrik.de/osmi/tiles/routing_non_eu/$z/$x/$y.png

Those marked (*), and additionally all the public transport views offered by OSMI, are currently only available for Europe. For the public transport views, use the URL components “ptri” (rail infrastructure), “ptnri” (non-rail infrastructure), “ptf” (ferries), “pts” (stops), “ptn” (network).

Note that the tiles for each view will always show all available layers at the selected zoom level; when using tiles, you cannot toggle the visibility of individual layers like you can when using OSMI through its web interface. Also, the key to colours and symbols is only available within OSMI. Therefore, even if you plan to use the tiles in your editor, it might make sense to familiarize yourself with the data presentation on OSMI first!

We hope that these changes help to further improve quality awareness and, in consequence, data quality in OSM, and we’re happy to work with potential sponsors on extending these services to support more frequent updates, additional analyses, or a wider geographical coverage.

A Night at the Office

30.11.2010 | Frederik Ramm

We are sometimes asked how we produce the files on our download server. Read this if you are one of those asking.

It is 22:30 in Central Europe, and the lights come on in the Geofabrik office. (The HDD LEDs, that is.) One of the servers, named bonne, begins downloading the collected works of mappers around the world from the last 24 hours

osmosis --rri --simc --write-xml-change 2010-11-16-22:30.osc (duration 00:01:30)

and then applies them to a locally held, full copy of the OSM database (the “planet file”).

osmosis --read-xml-change 2010-11-16-22:30.osc --read-bin current-planet.osm.pbf --apply-change --write-bin new-planet.osm.pbf compress=none (00:28:09)

The newly created planet file is transferred to another server, named hammer, where a script converts it to a simple CSV-like format (the “tbf” format) and then analyzes and converts it in several steps, creating statistics and a number of shape files. The shape files are later copied to our off-site tools server where they are used by the OSM Inspector.

But bonne, of course, doesn’t sit idle. More …

Today we finally received our author’s copies of our brand-new English OSM book. Old news, you might say; after all, this was featured on opengeodata.org a month ago. But it took a while for the books to reach us here at Geofabrik — we’ve been told that the first batch of books had to be dispatched to the US immediately because of the high demand there!

As you probably know, Jochen and I published the first OSM book ever in spring 2008, in German; a second edition came out in 2009, and a third in 2010. The book is of course a niche product as books go — with roughly 4,000 copies sold altogether. But we’ve been getting great feedback from the community and were encouraged to do an English version basically from day one. And so we did! At first we toyed with the idea of doing the book on our own with a print-on-demand place like lulu.com but we tried a few and were unhappy with the results. It took us a while to find a proper publisher with whom we could work, but we finally found a great, if small, publisher in UIT (Cambridge, UK). Just as with the German book, we not only wrote the content, but also did the typesetting, layout, and book cover ourselves, and we are very pleased with the finished product. It looks, feels, even smells like a proper book.

OSM Book

We had great help from one of the old OSM hands in England, Steve Chilton, who made sure that the English version properly reflects the international aspects of OSM, and fixed up our translation. Like the German book, the English one has 384 pages, 32 of them in full colour. (The English language is a bit more concise than German, so we managed to squeeze in a few extra illustrations and examples!) It covers everything there is to know about OSM, from the origins and the community to web services, editors (with detailed descriptions of Potlatch and JOSM), how to render your own maps (including how to write Mapnik and Osmarender style sheets), and how to access OSM data through API, planet files, or diff updates.

If you’re serious about OSM, you should really get this book. (If only to prove to others that the project you’re spending half your waking life on is something serious, you know, something people write books about!)

The sad thing is, like so often with publishing, the distribution, or more specifically, amazon.com; you can order the book at bookdepository.co.uk (free shipping) and it is also in stock at amazon.co.uk, but amazon.com says it “ships in 1 to 3 weeks”. (Also, both amazon sites have the wrong cover image, reflecting an early draft.) I hope that these initial distribution problems will soon be flushed out. This is the one drawback of doing a traditionally printed book – the stuff has to be shipped from printers to wholesalers to retailers and all that takes time.

More information on the book is also at www.openstreetmap.info.

New file format for OSM downloads

22.09.2010 | Frederik Ramm

Geofabrik has been providing the OSM community with cut-down data extracts for various continents, countries, and smaller administrative divisions for over two years now. Our downloads at download.geofabrik.de form the basis of many community projects, and we’re happy to make working with OSM data easier for so many people.

Today we’re launching experimental downloads in a new binary format. The new “protobuf binary format” (.osm.pbf) is 30% smaller than the bzip2-compressed OSM XML, and it can be processed or extracted much faster than bzip2 files. Also, while we will continue supporting the bzip2 files for a while, we hope that we can ultimately free up some resources by dropping bz2 support, and use these resources to produce an even wider set of daily updated OSM extracts.

The protobuf binary format was developed by Scott Crosby and presented to the OSM community in April this year (wiki article with details). As the name implies, it relies on Google’s “Protocol Buffers” for its internal data representation. The format is supported by Osmosis starting with version 0.37; .osm.pbf files can be read directly by Osmosis, or converted to plain XML OSM first using a command like

osmosis --read-pbf myfile.osm.pbf --write-xml myfile.osm

The above command will run significantly faster than a bz2 decompression, and the .osm.pbf files made available by Geofabrik are 100% lossless. The format offers further compression options by stripping of metadata or minimally reducing precision, but Geofabrik extracts will remain lossless.

Not only are .osm.pbf smaller and faster to process than their bz2 counterparts; they are also likely to appear faster on the Geofabrik download site than the regular .osm.bz2 files. Everyone is encouraged to give them a try.

(Edit on 2010-11-16: Initially the command line options to use were called “read-bin” and “write-bin”, but later releases of Osmosis now use “read-pbf” and “write-pbf”.)

OpenStreetMap WMS servers are hard to come by – because they are hard to operate. Running a WMS server always means a trade-off. You can have it render from vector data which makes it slow, or render from pre-computed raster tiles which makes intermediate zoom levels and reprojection ugly. You can use clever preprocessing but then you’re unlikely to be able to trace OSM updates quickly, or you opt for high-frequency updates but that again causes more load on your server. You can use Mapnik but the available WMS servers for that are not so good, or you can use the established UMN Map Server or Geoserver which have excellent WMS support but don’t achieve what has become the “standard” look and feel for OSM maps.


Geofabrik WMS displayed in Quantum GIS.

We think we have struck a nice balance between all these goals with our WMS server, which is available to customers immediately starting from EUR 35 per month. (We regret that we cannot make this available for free due to the cost involved for us, but will consider granting free access for OSM community projects.) The server runs from a continuously updated OSM database covering the whole world, and offers a clean Mapnik vector-based rendering in all projections and sizes. More on our product page.

At the same time, we’re making the software that runs our WMS – a special module for the Apache web server that talks directly to Mapnik – available as Open Source under the GPL license, which should allow anyone to install and run their own WMS server. There’s more on the OSM wiki.