[Openstreetmap] The new pioneers of map making

SteveC steve at fractalus.com
Thu Mar 17 17:09:13 GMT 2005


The new pioneers of map making

     * 19 March 2005
     * From New Scientist Print Edition. Subscribe and get 4 free
issues.
     * Will Knight

   ARMED with a Global Positioning System receiver and a pair of itchy
feet, Jo Walsh walks a different route around town each week. She
   is slowly but steadily building a digital map of her neighbourhood in
Bristol, UK. In doing so, Walsh is reinventing the pioneering
   spirit, for she is one of hundreds of people using cheap,
off-the-shelf satellite tracking equipment to make their own maps.

   The principle is simple. Set your GPS receiver to record longitude
and latitude at frequent intervals during a walk, bike ride or car
   trip, then download the information to a computer and watch as it
traces out your journey on screen. And by combining data from various
   trips, you'll get a rough but usable digital map of the world you
live in. "You just need a GPS receiver and data cable and then anyone
   can do it," says Walsh's husband and collaborator Schuyler Erle.
Together they have co-authored a book on digital cartography, Mapping
   Hacks, to be published next month.

   But why build a map when there are perfectly good ones in shops or on
the internet? In the UK, and most of the rest of Europe, the
   answer is simple: maps cost money and are protected by copyright.

   Home-spun digital maps, on the other hand, are free. What's more,
they have massive potential as a new information resource. By
   including various features not on standard maps, they can provide a
wealth of extra neighbourhood information. This might include the
   location of shops, landmarks, newly installed road works, or even a
traffic accident. Annotating digital maps with such information has
   even caught the imagination of technology giant Google, which
recently launched a mapping service, Google Maps, so far covering only
   the US and Canada (http://maps.google.com).

   But for self-professed "map hackers" like Walsh and Erle, it's about
more than just locating the closest Starbucks. "It strikes at the
   heart of what it means to be part of a democracy," Erle suggests.
"Access to geographic data constitutes a public knowledge
   infrastructure that our society operates on."

   Although the technique is imperfect - GPS is only accurate to about 5
metres - combining data from several trips can build more
   accurate maps. "With the availability of satellite tracking, we are
going to see a flurry of these projects starting up," says Michael
   Batty, a cartography expert at University College London.

   Gathering the information is just part of the problem, however.
Putting it together and making it easily accessible may be a grander
   challenge. In the UK a new online service could help. OpenStreetMap
(www.openstreetmap.org) is designed to let people upload home-made
   maps to a central database that patches them together into a single
grid that can be searched online. And there is a simple trick that
   could fill in details not yet mapped by GPS volunteers. Roads, rail
lines and other features can be traced from commercial satellite
   images, and information produced in this way is not covered by
copyright.

   A mapping group called LondonFreeMap
(http://uo.space.frot.org/?LondonFreeMap) hopes to map Greater London
this way. And its
   programmers are working on image-processing software to generate
sketches from bird's-eye views. Even in the US, where government-made
   maps can be freely reproduced, hundreds of volunteers are collecting
geographical data about their surroundings. "There's a large
   movement to create a geospatial web," says Michael Liebhold, senior
researcher at the Institute for the Future, based in California.

   Building this geospatial web is about matching geographical
information to the wealth of information that already exists online, by
   linking web addresses with real locations. "You can imagine being
able to open a mobile computer and find out everything about the area
   you are in." Liebhold says. "We're building a worldwide atlas."
   From issue 2491 of New Scientist magazine, 19 March 2005, page 26

Classic cartography

   Map-making is one of the oldest human technologies. The earliest
known maps were created in the 5th millennium BC, and emphasised
   boundaries and simple special relationships between objects.

   Maps then became increasingly sophisticated as they incorporated
lessons from mathematics, astronomy and engineering. Babylonian
   scholars introduced geometry in around 2300 BC to help codify
representations. And in the 2nd century BC, Greek philosophers began
   incorporating the principles of longitude and latitude into their
maps.

   In the 15th century AD, European explorers such as Columbus and
Magellan carried cartographers equipped with quadrants, compasses and
   hourglasses to the New World. And atlases created by the 16th-century
cartographer Pierre Desceliers highlight the desire to add
   information such as wildlife and cultural boundaries.

   Today, satellite tracking and imaging technologies are used to map
the entire globe, and now home computers and the internet are
   enabling ordinary citizens to take a lead in map-making, by
annotating geospatial data with personal information.



have fun,

SteveC steve at fractalus.com http://www.fractalus.com/steve/




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