I spend a lot of time looking at maps. I’ve been called “the human map.” Cartography is one of my interests. Photography is another.
I use Runkeeper when I’m taking photos with my digital SLR, and later match up the GPS tracks to the photos in Lightroom. But every now and then there’s a photo that just doesn’t match up and you’ve got to manually assign it a location. Normally not a problem.
I noticed in August last year that my GPS tracks, when overlaid on Google Maps in Adobe Lightroom, would point to the wrong place on the map. I toggled to the satellite view, and the photo looked like it is in the right place. But you switch back to the map view and its in the wrong place again. What gives? Notice in the example below, from Chengdu, China, that the park has moved but the “A” location icon stays in the same place. From my GPS data, I could tell that the satellite maps were spot-on, but the road maps weren’t even close.
A quick check of Baidu Maps and Soso Maps (two Chinese companies) revealed that everything was lined up perfectly. Microsoft’s Bing Maps, on the other hand, were so far off as to be completely unusable. I started checking other parts of the world — North Korea, Afghanistan, Russia — and they all lined up without this issue. You can even take a look at Hong Kong, where everything lines up, then move just 100 yards over the border to Shenzhen, China, and things are offset again.
Some investigation reveals that the cartography (the map on the left) has been shifted by a random amount (about 0.025°E,0.025°S in Chengdu, but 0.06°E in Beijing) due to Cold War era Chinese regulations.
The net is that the map offsets are not a bug, but rather intentional. There is a secret fixed website at ditu.google.cn. Okay, not secret, but how you would normally find it, I have no idea (thanks MDW for the link).
This isn’t the first time Google has altered its maps to meet Chinese regulations. Both Apple and Google duplicated the Diaoyu/Senkaku islands so that, from a cartography point of view, both China and Japan could own them. Clever.
Not all is lost, however. There are some very clever map enhancements out there. Google had their 8-bit maps. My personal favorite is the SimCity-style maps from Baidu (the map image at the beginning of this post). Very cool.
XKCD always has a special place in my heart, and this comic hit home. Yes, I probably have spent more time looking at Google Maps in the last 10 years, than playing video games.