All Maps in China are Transformed (opens in new tab)

Indeed, the hole point of the projection was to make navigation easier by allowing rhumb lines (the shortest distances between two points on a curved surface) to be charted as perfectly straight lines on a two-dimensional map. From these lines of constant bearing, mariners could work out the precise - and constant - angle they should maintain in relation to the pole star in order to get from one point to another.

Without a reliable method for establishing longitude at sea, 17th Century navigators could never be exactly sure how far along their courses they were, but at least they could know that they were heading in the right direction. Given the level of uncertainty involved in these enterprises, this one piece of (relatively) hard and verifiable data was extraordinarily important, making the accuracy of the projection, and the mathematically - if not visually - correct placement of shorelines within it especially important.

Unfortunately, the iconic value of the Mercator projection has vastly outlived its utility - or at least, the common awareness of the once formidable navigational problems it addressed. Far from seeing it as a brilliant technical solution, it is often seen through a purely political filter that views its strengths as weaknesses, while completely missing the map's actual intent.

All 2D map projections produce either distortion or discontinuity. Neither of these affects a map's functionality in the way that outright inaccuracy does.

http://maps.google.com/maps?q=Huashan+Road,+Shanghai,+China&...

The locations are all still off and they're consistently off by an offset throughout Shanghai. There might be some deliberate dishonesty by map makers in China, but I don't think this is evidence of it - I think this is just an inaccurate projection. If you want to make bad maps to confuse people - first, that's probably pretty impossible with current information systems, even in China, and second, this would be a really bad attempt at it.

An interesting anecdote from my side, though not necessarily map-related. But in the same theme as gp. This summer, I was volunteering teaching English to rural kids in China. One of the kids kept writing this big message on blackboards and stuff that Osama bin Laden was still alive. One of the local volunteers read what he was writing and was upset at him for fooling around so much. Later, I asked her what's up, and she told me what he was writing.

WTF.

So in the team meeting later that night, I talk with my fellow volunteers about this, and wonder if I have some kind of crazy kid on my hands. Then the Chinese volunteers told me not to worry about it, he's just writing stuff. I'm like, "What do you mean, how do you know?" Then they started talking about how people distrust the government these days, are unhappy, etc. I'm like, "What the heck does that have to do with anything?"

Turns out that all over the Chinese web, this was a really popular meme where Chinese youth displayed their sarcasm at anything the government said. Even things that they knew to be true could not be true because the government said it. It was only a meme, much like the Hitler videos we see on Youtube.

Scared me for a day.

But suffice it to say, people in China aren't so trusting of what their nation says as before. Living here, I hear it from my colleagues and friends every day. That being said, there's very little right now that they can do to voice their opinion because it's still a touchy atmosphere.

This lady is very informative. http://www.ted.com/talks/lang/eng/yang_lan.html

Or, people have it ingrained in them that Taiwan is small, and they all know that Chinese map-makers are politically motivated, so they assume that all map-makers are equally politically motivated.

No.

Later, she, another friend from China, and I had a more in-depth discussion about Taiwan. It was really interesting to get that perspective.

P.S. I have no idea why you're being downvoted either.

I'm not questioning the advantage (in my view it's a small roadblock if you're motivated enough to actually get the data) just stating an inane regulation...

The case of Taiwan is even more confusing. A world globe I have from a decade ago, commercially published by a private business corporation rather than officially published, shows Taiwan and the mainland territories of China in the same color. (Usually this globe distinguishes different countries by different colors.) However, the globe also marks the location of both Beijing and Taipei (so spelled) with a star symbol indicating a capital city, suggesting that Taipei is the seat of a national government. United States law under the Taiwan Relations Act strikes a delicate balance between agreeing with the original assertion of both the P.R.C. and R.O.C. regimes that there is one China and Taiwan is a part of China and the current facts on the ground that China (the P.R.C.) and Taiwan (the island of Taiwan and various outlying islands, including some that historically were part of Fujian Province) are under distinct national administrations.

The Wikipedia article on Taiwan independence

http://en.wikipedia.org/wiki/Taiwan_independence

seems to have enjoyed some good editing back-and-forth so that it is not entirely slanted to one point of view or another.

Which is pretty humorous since, once you're vaguely close to it, it's hard not to find it. If they built several other pentagonal buildings in the area, it would be a different story. :-)

The problem of OSM in China is its limited data-set. For example, in the city I developed the project OSM had only the major streets, and the map was quite old.

And if you want to know the depth of a ford, well you can go and measure it.

So I really don't get why they would make them secret.