Thursday, October 20, 2011

Transformers - navigation in disguise

No, I haven't got a special outfit to wear while I read maps... but that's not a bad I idea now I think of it. Maybe some kind of checkered theme would go well with the grid lines? But, I digress. I also haven't written anything about Hainan, and now the iron is cold I probably won't. Luckily Lina wrote something.

One excellent thing we brought with us to China was our GPS. This device proved very useful on our trip down the Yukon River using the tremendous Ibycus Topo maps. I had high hopes of it helping us find our way around China. Navigating here is particularly challenging because we can't read the road signs and new roads spring up at such a rate, bu the time you turn around to go home, there might be a motorway where that country lane used to be. Having some record of where we went seems very wise. However, nothing worth having is ever easy... and GPS mapping of China is certainly a challenge.

The first problem is that GPS maps in China have a well described problem of being "offset" or "transformed" from the point your GPS unit will tell you you are at. Reasons for this seem to be some kind of government bureaucracy which serves the purpose of allowing more money to be extracted from Garmin, Google,  and all the other electronic mapping behemoths that own the pictures of the Earth's surface, the front door of your house, and you walking out of the supermarket with your face blurred out. More adventurous thinkers who write on the internet suggest conspiracy theories, fear of American invasions of China, and protection from intelligent alien parasites as the reason for the GPS offset. I don't know about all that, but I do know that my GPS tells me I am riding my bike in the sea when in fact I am on a road. This can be mildly amusing but makes it impossible to navigate around a town using the GPS. Out in the countryside of Hainan we found we could still get a good idea of where we were, how far to the next town, and that sort of thing, but the GPS screen always showed the offset.

The blue line is our real position, the orange line is where the map tells is the road is. I swear we were riding on the road...

There are various ways that people on the internet have discussed fixing the "offset problem", some more elaborate than others and mostly ineffective on my GPS when I tried them.  Given how much effort it had been for me to get a decent street map of China on there in the first place, I was losing interest in losing more of my life reading about gmapsupp files on GPS enthusiasts internet forums. So I forgot about it for a while.

Unfortunately, I can't forget about unfinished business. More internet digging revealed the mysteriously named Venus Series maps. It seems from the description that someone has taken it upon themselves to re-calibrate the Garmin City Navigator maps to that the offset problem is fixed, or at least greatly reduced. After some fairly extensive internet foraging I managed to download the map and now just have to get it to work on my GPS. I expect this to be no mean feat judging by my previous experiences... but how else could I while away those long winter evenings? To be honest, I could think of many ways... but I will persevere.