Simon Willison’s Weblog

8 items tagged “gps”


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

GPS and Relativity (via) GPS satellite clock ticks need an accuracy of 20-30 nanoseconds. The satellites move fast enough that their clocks fall behind by 7 microseconds a day due to time dilation, but orbit high enough that the curvature of spacetime due to the Earth’s mass puts them forward by another 45 microseconds. GPS receivers have to perform relativistic calculations to determine their location! # 11th January 2010, 9:17 am


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


Tracking your Cat with GPS. Alex Lee strapped a GPS to his cat. # 6th October 2008, 9:16 pm


New A-GPS service for Nokia phones. Appears to look up your cell ID against a global database to find nearby satellites, dramatically reducing the time needed to get a GPS fix. # 6th August 2007, 11:26 pm

Talking to the internal GPS in my N95 from Python. Thanks to a new LocationRequestor module for Python Series 60. # 6th June 2007, 10:31 am


Mapping the postal network. Image of a GPS trace for a unit that was left on and sent in the post. # 20th December 2006, 12:43 am

Holux GPSlim (GR-236) Review. Matt Biddulph has one of these. They’re awesome. # 7th July 2006, 1:56 pm