All licensed London taxi drivers need to pass a special test before they can drive one of the Capital's famous black cabs. This test is called the Knowledge.

How long it takes to become a licensed taxi driver depends on whether you want to be an All-London driver or a Suburban driver.

London or the suburbs?

All-London drivers - also known as Green Badge drivers - need a detailed knowledge of London within a six mile radius of Charing Cross.

All-London drivers' Knowledge is based on learning 320 routes (or runs). This will help them learn the 25,000 streets and 20,000 landmarks and places of interest in the six mile radius of Charing Cross.

It takes between two and four years to pass the All-London Knowledge. Once you are licensed you can work anywhere in the Greater London area.

I generated a new charge of history extracts, based on the 120213 full
history dump. They have been created from the latest
full-experimental-dump [1] using my history splitter [2], based on
Jochen Topfs really great osmium framework [3]. They contain multiple
versions of an object. If you just want the map-data as it is today, use
the Geofabrik-Extracts [4].

The extracts can be downloaded from a server of my employer:
<http://osm.personalwerk.de/history-extracts/>

Their size ranges from very small (a village) via medium (Berlin) to
large (Germany), touching various countries. They only cover a very,
very small part of the world and are currently targeted at application
developers that are looking for data to test their history analysis
apps. Most extracts are delivered as .osh.pbf files, readable with all
history-enabled pbf parsers (eg. osmium).

Some extracts are also available in the .osh.bz2 format (xml-basesd).
Some common programs like JOSM can open them them when you rename them
to .osm, but the produced output is not very useful in most cases.

In contrast to the last set of extracts, the new ones are now cuttet
using the softcut algorithm [6] using simple bounding-boxes [5].

Dumps created using that algorithm have the following characteristics:
- ways are complete (as they are in the api-database)
- ways are reference-complete (all referenced points are included)

- relations are complete (as they are in the api-database)
- relations are NOT reference-complete (relations may reference ways
or nodes that are not in the extract)

- relations referring to relations that come later in the file are
included

- all versions of an object of which one version touched the bbox are
included

What are the relations between digital cartography and hand-drawn maps?
The science is dividing the field of knowledge into disposable knowledge and reusable knowledge. Google maps are falling into the first category, while axonometric maps belong to the second, because they're suitable for being reused. An 11-year-old hand-drawn map still looks beautiful, whereas 11 years from now Google maps will be dated. Google and others are failing to present the beautifulness of our planet to us when doing their digital atlases.

Are you familiar with Baidu? The Chinese can't show satellite images of their cities so they model these detailed axonometric cityscapes.
Baidu shows very beautiful representations, similar to hand-drawn maps. They're like the depiction of a promise, telling you that it's a beautiful country to live in, whether it's true or not.

Reparieren leicht gemacht (1972), Verlag Das Beste, Stuttgart, 23 x 26 cm, 568 pp
Do you think the actual possibility of processing big datasets will affect other fields of visual design beyond data representation?
The digital has had a great impact not only on the production of information, but also on how to get to the sources. But this speed comes at a cost that shouldn't be underestimated, and that cost is precision. In the early days, information designers controlled the entire process and physically possessed the information. Nowadays, if you're doing a data visualisation using bytes that aren't on your hard drive, or that you don't even own, then you're dependent on other people. That's the digital drawback. The moment authoritarian countries decide to cut the wires, all the knowledge will be gone.

Oakland Policy Plan for 1980, scanned by Eric Fischer

"Fellow Nestoria fans, this week we went live with a significant change to our service - in most countries we've moved away from Google maps and are now relying exclusively on OpenStreetMap maps served by MapQuest.

...

At the time, looking at Steve as he showed me the GPS device he was using to map the details of our meeting (which took place in a little cafe in Soho across the street from the John Snow pub), the idea of creating a viable map via volunteer submissions seemed preposterous in the extreme. But I watched as OSM grew and grew from those humble beginnings. Now, less than six years later, that map powers Nestoria thanks to millions of man hours of contribution by individuals and organizations that recognize the power of open data."

"Wikipedia articles can be tagged with latitude/longitude coordinates. I was recently curious to know: which areas have the most coverage? It's important not to read too much into the answer, because the density of coordinates is due to a mixture of: how active different Wikipedia language projects are, how active at geo-tagging they are, which regions have had lots of short articles mechanically imported (e.g. on small towns, or metro stations), and finally, the actual landmark density (e.g. dense urban cores versus sprawling suburbs). But nonetheless it might be interesting to know.<br />
<br />
So, here are the most densely Wikipedia-article-populated parts of the world, at several scales."

"building=yes is a searchable and linkable index of every single way tagged building=yes in OpenStreetMap (OSM).<br />
<br />
A web page for every building in OpenStreetMap!<br />
<br />
You can link to buildings using their 64-bit building=yes identifier or their OSM way ID.<br />
<br />
Each building has been tagged with one or more Where On Earth (WOE) IDs so you can also search for buildings by place."

"This is a tough question here, in Novosibirsk, where almost all PC users know 2gis, the desktop city map/yellow pages with a huge business database and public transport routing. It's free to get and to list your business, but completely closed source, both data and the software. ... This model was invented in 1998 and is pretty outdated, but all together still manages to satisfy the users.<br />
<br />
...<br />
<br />
So, Novosibirsk is their native city. Everyone knows 2gis. When someone needs to go somewhere, they open 2gis and search the address.<br />
<br />
I find few areas and people who could be interested in using and contributing to OSM. It's a tough question. That's why last several months I have been drawing rural areas and small towns, the places in which 2gis will never be interested, or will have not enough resources to map."

"Yay, I get to explain my 'Levels of Boston Navigation', developed as I tried to learn my way around Boston...:<br />
<br />
Level 0 - Navigation by street name) You find where you want to go on the map, and write out the route Google-maps style.<br />
Level 1 - Landmarks) You learn where key landmarks are, and the names of some of the larger 'squares'.<br />
Level 2 - Used-to-be) After you've been in the City for a while, you learn to give and take directions based on what used to be at an intersection.<br />
Level 3 - Gonna) The most advanced level. Involves giving directions based on what they were going to build, but never actually did."

"Following a two-year pilot program sponsored by Council member Desley Brooks, and with the support of Chief Anthony Batts, Urban Strategies Council has come on board to assist the Oakland Police Department with crime mapping and analysis in late 2010, helping the entire department develop new crime prevention tactics, usable mapping, and resource management. Junious Williams, the CEO, said, 'This type of public-private partnership is critically important to effectively tackling social problems like crime. We look forward to establishing similar partnerships with other public agencies.'<br />
<br />
...<br />
<br />
Since the inception of this partnership, the first in the entire state, the Council has been delivering valuable crime analysis and mapping to key police personnel on a weekly basis. This intelligence is tailored to meet the distinct needs of Oakland law enforcement and supports dozens of senior department staff and beat officers on the job."

"Sha has coined the term 'NoGIS' to describe the work of mapping technologists like myself who don't have a traditional GIS background (as a nod to the NoSQL movement away from traditional databases). Software like Mapnik and Polymaps have done so much to make it easy for even inexperienced developers to make large GIS applications without the steep learning curve of ArcGIS and CAD software. That's the direction I see our field moving towards: map technology built explicitly for the web, rather than traditional mapping concepts ported to the web."

"The most valuable thing about this habit, though, is not the post-mapping analysis but rather the motivation it generates to get out and explore and get to know new parts of the city. I'm sure you can imagine the thrill of getting to draw a line on a new part of the map. Doing all this without GPS keeps my mind sharp, too, because I must always be aware of exactly where I am so that I can later mark it on the map. My local expertise in transportation and geography is skyrocketing because of this little project."

"In general, black is walking, red is bicycling, blue is cars or buses, and green is above-ground rapid transit or freeways. Not shown: tunnels and subways."

"In order to respond to the current cholera epidemic in Haiti, it's essential that citizens, aid groups and others are aware of the locations of functioning health and sanitation facilities. The challenge is that maps showing this information don't currently exist -- at least not in a comprehensive and up-to-date way.

Guensmork Alcin is attempting to change this. He is working with the International Organization for Migration (IOM) to expand OpenStreetMap, a free and open source map of the world that has one of the most detailed GIS data sets in existence on Haiti."

Muki Haklay:
"In the presentation, which is based on my work, as well as the work of Vyron Antoniou and Nama Budhathoki, we argue that geography is playing a 'tyrannical' role in OSM and other projects that are based on crowdsourced geographical information and shapes the nature of the project beyond what is usually accepted."

"Liz and Tim are in Chicago giving a series of mapping workshops and making contact with some of our collaborators up there.

...

One big point of discussion was how to deal with the embedded biopolitics behind data sources like US Census data that we use in our maps - as 3Cs, we often talk about how we 'queer' data or statistics by pulling map stories out of them that they weren't intended for. But data sources often come so tightly bound up with state politics, white supremacist racial policies, definitions of family structure, etc., that queering them might require more conscious work than we always put in."

Jeff Warren is raising money for his ongoing aerial kite mapping in the Gulf:
"We are a group of citizens and activist mappers who are documenting the effects of the BP oil spill in the Gulf Coast with a set of novel DIY tools -- we send inexpensive cameras up in helium balloons and kites, and take aerial photos from up to 1500 ft. The data we're gathering will be vital in both the environmental assessment and response, as well as in the years of litigation following the spill. All the imagery we capture is released into the public domain and is free to use or redistribute.

We need support to keep a supply of helium, and to pay for gas, kites, cameras, and protective gear for our volunteers."

"This work as its name indicates extends over the field of plane surveying. It illustrates and describes the instruments employed, their adjustments and uses; it exemplifies the best methods of solving the common problems occurring in practice and furnishes solutions for many special cases which not unfrequently present themselves. An experience of twenty years in the field and in technical schools confirms the opinion that a work of this kind should be eminently practical; that the student who desires to become a reliable surveyor needs frequently to manipulate the various surveying instruments iu the field to solve many examples in the class-room, and to exercise good judgment in all these operations. With this in view, therefore, the different methods of surveying are treated, directions for using the instruments are given, and these are supplemented by numerous examples to be solved, by various field exercises to be performed, and by many queries to be answered.

"Use Cartagen Knitter to upload your own aerial imagery and 'knit' a map. Everything you create with this tool is owned by you; read more at GrassrootsMapping.org.

Watch a short video demo of how to use this tool..."

Muki Haklay on socieconomic diversity in OSM:
"Instead of shrinking, the gap between affluent and deprived LSOAs (Lower Level Super Output Area) is growing. The average completeness of the bottom percentile in March 2008 was 40.7%, grew to 65.7% a year later and to 71.8% by October 2008. For the most affluent percentile, completeness grew from 67.5% in March 2008 to 97.0% a year later and to 108.9% by October 2009. In other words, the gap between the top and the bottom has grown from 26.6% to 37.1% within the analysis period."

I say make a game out of it.

Thematic mapping for Google Maps - uses Raphael JS and the Google Maps API to do few basic cartography tricks: choropleths, dot plots, etc.