Automatic Packet Reporting System — APRS — is rather clever. It’s a way of reporting position, status or messages via the amateur radio 2m band. Data is relayed via digipeaters, and routed to/from the internet APRS-IS system to any user worldwide.

It’s a little fiddly to set up, even with a very polished (read: $$) handheld radio like the Kenwood TH-D72A. I’m a bit disappointed that the purported SiRFstar III GPS in this radio takes forever to get a lock, but it’s a nice radio despite this.

The screenshot above shows aprs.fi‘s tracking of my handheld (VA3PID-7) last night as I walked to Toronto Mappy Hour.

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… or “トロント動物園“, as we locals purportedly call it. The This place has unverified edits legend is a bit of a giveaway. Looks like there’s been some messing about with Google Map Maker, which isn’t always the best tool for the job.

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My GPSMAP 60CSx had started to become unreliable: crashing after startup, randomly locking up in mid route, and just generally being an aggravating piece of kit. I was really close to replacing it.

The problem seemed to appear after I’d used USB Mass Storage to transfer archived track logs to the computer. As a last resort, I tried removing the hidden files that OS X creates on every removable disk, and now all is well. It’s annoying and inexcusable that Apple chooses to do this, but we work around.

To delete these files from the terminal and eject the device safely, enter these commands:

pushd /Volumes/GARMIN/
rm -rf .Spotlight-V100 .Trashes ._.Trashes .fseventsd
popd
disktool -e disk1

Your device might not be called /Volumes/GARMIN/, so check and change appropriately. If you have multiple drives on your machine, your GPS is probably not the disk1 device. You can find out which it is by entering disktool -l.

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I walked a local footpath carrying my (mostly) trusty Garmin GPSMap 60Csx, and a Blackberry Tour running bbTracker. Both had had a good satellite fix for about 10 minutes beforehand, and both were logging trackpoints every second. The smooth turquoise track from the Garmin is much more useful than the wibbly one from the Blackberry.

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It was fun – there were geo-aware cupcakes!

• It is very easy to lose days in the David Rumsey Historical Map Collection.
• Richard’s OpenStreetMap for the Beginner tutorials are actually really really good.

In a moment of geek worlds colliding, Emma showed up, and now I have people clamouring for tablet at Mappy Hour. Sigh, those old ecommons links just don’t fade …

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I went for a bike ride on Canada Day. Click on a bicycle icon to see what I saw.

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Note: I’ve had reports that some carriers seem to disable GPS service within their service area. I’ve certainly seen slight differences as to how this works on different carriers.

Most recent camera-equipped Blackberrys have a GPS built in. One of the most handy things I’ve found for fieldwork is the ability to take pictures tagged with your location and be able to send them to contacts.

Setting this up is a little involved. First, go into the camera, and selection ‘Camera Options’. You want to enable Geotagging:

(oh, and I took the screen capture with CaptureIt). Save options, then exit back to the home screen.

I find the most reliable way of starting the GPS is to go into Blackberry Maps, and ‘Start GPS Navigation’ from the menu. Once you’ve got a reliable satellite fix (which on my old Curve, used to work fine indoors; on my Tour, not so well) you should be able see the map update with your current location, and a satellite count (9 here) on the bottom of the screen:

Exit maps, and start your camera. You’ll know if you have a location for tagging if there’s an icon that looks a bit like  in the bottom right corner of the screen. With no fix, it’s a red crossed-through icon. Now take your picture!

(yeah, my Blackberry takes slightly fuzzy pictures. Dunno why.)

Metadata’s only useful if you can read it, and on anything with a command line, ExifTool works really well:

$ exiftool IMG00144-20100411-1516.jpg
 ...
GPS Position                    : 43.709983 N, 79.239817 W

(one should note that without a barometric pressure sensor, GPS altitude readings are not to be trusted. This picture claimed to be taken at 120 m Below Sea Level …)

Curiously, OS X’s Preview gets GPS position completely wrong:

According to Preview, I and my bike (and my Blackberry) were close to Charyn in Kazakhstan. I’m quick on my pedals, but not good enough to get far east in an afternoon.

iPhoto gets it right, though:

Curiously, I couldn’t find anything built into Windows (okay, XP) that would read the tag location. I guess Microsoft just don’t want you to know where you are now, merely where do you want to go today.

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Mark asked: What kind of GIS software are you using?
Well, since you asked:-

• SpatiaLite: spatial awesome built on SQLite. I love it because I don’t need to play DBA.
• QGIS: for maps
• ogr: for file format futzing
• proj: for scrupulously correct (well, if I knew what I was doing …) conversion between projected and otherwise.
• OpenOffice: for those tedious calculations
• … and about 20 years of unix experience to mash all the results together.

All of the above are free. I’m doing this because I want to learn. Asking elsewhere hasn’t turned up anything useful.

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I’m rather taken with the symbol that Japanese maps use for wind mills and wind turbines. I’ll try to modify it for use in QGis.

Update: so how does this look?

I cleaned up the blade angles, added line end-caps, and made all the white bits transparent. Works fine in QGis.

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