Wednesday, August 29, 2007

GPS Shenanigans

I had a GPS (Garmin GPSMap 60CSx) for the first time, to take on a long sailing holiday, to be able to geotag all of the photos I took and maybe publish some tracks to Google Earth.

How did it go?

Not all plain sailing ....... here are some of the issues.

Maps were the first problem. The basemap on my GPS, showed no landmasses for most of the islands in the West Indies. I had managed to find a good Open Source map of the area just before leaving, but was unable to load it onto the device.

The first problem (got stuck on this while away) was I had updated MacOSX to a version that broke USB connectivity in Parallels (needed to run the MapsSource uploader), so the GPS was never going to connect to Windows. The few net connections I found while away were so bad I was not able to find this out, let alone solve it until I returned.
Once that problem was solved, I tried to upload the maps. Windows would crash after about 10 minutes (of 40) of uploading. No go, must be an instability in Parallels. Next I tried the new beta Mac MapInstall from Garmin. It just refused to do anything.
I finally got to run MapSource under VMWare Fusion instead of Parallels, the transfer worked first time. I have the map on a chip now, but of course I am no longer in the West Indies :)

The next problem was battery life.
When I was doing my online research before buying my GPS, I saw many otherwise attractive units with stated expected battery life of like 3 hours. That is so useless I have no idea why anyone would buy one. I was attracted to the Garmin unit I bought, because it was supposed to have a 40 hour battery life on two AA batteries, still too short IMHO, but becoming reasonable.
As it turns out, 40 hours is an outright lie. With two high power throwaway batteries, you would be lucky to get 10 hours. I do not like to use disposable batteries, so I bought a set of the highest power rechargeable batteries I could find, Nickel Metal Hydride rechargeables with a stated 2700 mAh capacity. The unit has a special setting for Ni-MH batteries (lower voltage, run slower) but I would struggle to get 5 hours.
Keep in mind this is 5 hours of the unit just making a track, not 5 hours of heavy interactive usage, calculating routes, displaying complex maps!!! 5 hours is not enough. It became too difficult to keep batteries charged and changed (power is always a bit ropey on a boat).

So I have ended up with incomplete tracks of my trip, very frustrating considering how much money I paid and effort I put in.

I have now geotagged all of my photos (using HoudahGeo), the tracks did help.
Next I'd like to play with making them into KMLs for Google Earth.
One problem I am facing is if you leave the tracking on while stationary, you get a rat's nest of spikes and squiggly lines as the boat swings on it's anchor and/or the accuracy of the GPS varies. Now I need a good track editor (suggestions anyone?).


What will I do differently next time?

1. Prepare maps before I leave.
2. Bring an adaptor that allows me to run the GPS off the boat's 12V power supply.

2 comments:

ryandbrimhall said...

Hey Jeremy,

Did you ever find a track editor that worked? I am wanting to do exactly what you did. Map my travels. Did you find a way to clean up the track you made?

Jerm said...

Thanks for your response.
Did you read my next post?
I simplified the tracks by filtering in gpsbabel.
You can also edit tracks in Google Earth, but it is not exactly a pleasant experience ...... is it just me or are Google crap at making GUIs?