In which I admit I am a dork (Signifying Nothing: how does saying nothing at all become so loud?)

Sunday, 25 January 2009

In which I admit I am a dork

Instead of doing something productive today, I spent the day in San Antonio at an OpenStreetMap mapping party. I got to meet some interesting folks and play “OpenStreetMap teacher” some, and it’s nice to be reminded that at least one of my dopey childhood hobbies has some practical application in the real world. And of course I got to put some more miles on the new car, which was fun too.

Thanks to the folks at CloudMade, and particularly their community ambassador, for putting the meeting together as well as for the swag. I can’t quite figure out how they think they’re going to make money off of OSM, at least until the OSM data gets in a lot better shape, but I suppose that’s their problem and not mine.

By the way, for those who’ve hung on until this point (or were actually looking for some useful OpenStreetMap advice), here’s my GPSBabel recipe for converting NMEA track logs from my Amod AGL3080 GPS logger into GPX track logs that can be imported into OpenStreetMap:

gpsbabel -t -i nmea -f infile.log -x simplify,error=0.0005k -x discard,hdop=6 -o gpx -F outfile.gpx

Basically this throws out bad GPS fixes and simplifies all of the data to throw out any points that would deviate from the current straight line by less than 0.5 meters. At least with the Amod GPS unit once it’s got a good fix it seems to stay pretty accurate, even with the “static navigation” feature off (using the “SN OFF” firmware), as long as you don’t leave it somewhere under partial cover.