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All Maps in China are Transformed

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Re: All Maps in China are Transformed

#61

Post by nate_meurer »

bahman2000 wrote: post #11

i don't think it's unique to China take a look at this POI on 4sq: http://4sq.com/rArZMj It starts with a street view. If you zoom in a little, turns out the bar is out in the water! When you switch to Satellite view, the bar is where it is supposed to be, on the shore.

I don't see the anomaly you're talking about. At any rate, it was probably just that -- an anomaly in the mapping software -- which is completely different from the government-mandated misinformation that is the subject of this story.

Re: All Maps in China are Transformed

#62

Post by alexqgb »

rmc wrote: post #46
marshray wrote: post #30

Back in the early 90's (in the US) I had a friend who was a college student from China. In the common area of her dorm there was a huge wall-size Rand-McNally map of the world. We were looking it over. "There's China" I said. "And there's Taiwan." "You know Taiwan is really not that big." she said. "What do you mean?" "Map makers show it larger than it really is in order to exaggerate its importance." I was a little…

those would have to be accurate in order to function The most common form of map, Mercator projection, greatly distorts the area of land around the equator, and makes northernly (& southerly) lands appear much larger. It makes Canada, Greenland, Alaska, et al. appear quite large compared to Africa & South America. But those areas are much larger. http://en.wikipedia.org/wiki/Mercator_projection#Uses

The Mercator projection isn't a good example of a map in which visual distortion and a lack of navigational utility go hand in hand.

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.

Re: All Maps in China are Transformed

#63

Post by jackfoxy »

Historically maps have been closely guarded military secrets. As late as the Renaissance possession of the wrong map could get you executed by European powers, even in peacetime. Rudyard Kipling's novel Kim is largely based on the true story of British surveying and map making in India and central Asia.

Re: All Maps in China are Transformed

#64

Post by azov »

jackfoxy wrote: post #63

Historically maps have been closely guarded military secrets. As late as the Renaissance possession of the wrong map could get you executed by European powers, even in peacetime. Rudyard Kipling's novel Kim is largely based on the true story of British surveying and map making in India and central Asia.

AFAIK, military maps are still secret in most places. This is because they contain information that cannot be easily derived from hi-res satellite imagery. Stuff like "how much weight can this bridge support", "how deep is this ford", etc. This is important if you are trying to, say, drive tanks through unfamiliar terrain.

Re: All Maps in China are Transformed

#65

Post by cleaver »

I did see exactly the same thing in Toronto for some time. The satellite image was misaligned with the street map for the Jane/Finch area. It's fixed now.

I do wonder how much trouble Google goes to fix up maps in China. I can't really see enough of the map to tell if this appears to be deliberate distortion, or just another error.

Hopefully Google is still keeping their maps up-to-date... When I was in Beijing, I found the Google map much easier for finding bus routes that the local alternative.

Re: All Maps in China are Transformed

#66

Post by rmc »

nate_meurer wrote: post #57
rmc wrote: post #46

Earlier quoted context omitted.

those would have to be accurate in order to function The most common form of map, Mercator projection, greatly distorts the area of land around the equator, and makes northernly (& southerly) lands appear much larger. It makes Canada, Greenland, Alaska, et al. appear quite large compared to Africa & South America. But those areas are much larger. http://en.wikipedia.org/wiki/Mercator_projection#Uses

Mercator distortion has nothing to do with the anecdote in the parent post. There the allegation was of deliberate inaccuracy, which renders a map non-functional for most purposes. All 2D map projections produce either distortion or discontinuity. Neither of these affects a map's functionality in the way that outright inaccuracy does.

Oh yes, I agree that this is an example of purely the geometry, not a political attempt. But I know people who , upon seeing the distortion, were surprised at how many maps were "wrong". This shows that you can't rely on the market to weed out inaccurate maps. After all, a map that had the south at the top (rather than the bottom) would be viewed as "wrong" and would be penalized with poor sales.

The idea that the market will always produce the best map is not true.

Re: All Maps in China are Transformed

#67

Post by georgieporgie »

marshray wrote: post #51
eob wrote: post #50

Here's a completely anecdotal, "a friend of a friend.." story, but I think it's a cool yi and you'll enjoy it: A friend of a friend is a cartographer who works in DC. According to this person, the official subway map of DC distorts the true geography of the city -- and the subway lines -- as much for security purposes as it does graphic design purposes. The red line, in particular, apparently is drawn with a complete…

Subway "maps" tend to be more like generalized graph diagrams than cartographically accurate maps. After all, you're stuck in a box and your only choice is which node to get off at. But it wouldn't surprise me if an overlay on a cartographic map was intentionally inaccurate. One time I was in DC a cab driver was trying to get me to my hotel. His GPS went totally nonfunctional when we were in view of the Pentagon. It…

His GPS went totally nonfunctional when we were in view of the Pentagon.

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. :-)

Re: All Maps in China are Transformed

#68

Post by rmc »

iliis wrote: post #41
rmc wrote: post #25

Earlier quoted context omitted.

no public-domain map data For the record there is no public domain map data in a lot of countries in Europe. The USA has the sensible approach of 'all government data (incl. maps) should be public domain'. In Europe the state owned mapping organisations do the mapping and claim full copyright on the maps & data. The 'illegal to make your own maps' is, obviously, not the case in EU

> In Europe the state owned mapping organisations do the mapping and claim full copyright on the maps & data. This is true here in Switzerland. You have to pay quite a bit for our maps. I think it's a good thing actually, because their quality is worth the price. They provide extreme detail even in very remote locations (well, remote for us at least ;)). And for doing quick lookups, there's a free online-map at http:…

Yep. OSM was set up by some people from the UK and the OS knows the location of everything that's more than about 20cm big and nailed down (from planning applications & surveying), so they have lots of high quality data.

However most people/businesses don't need that.

Just look at Google maps & OpenStreetMap. They don't have submetre accuracy, however there are still quite useful to people and businesses.

Re: All Maps in China are Transformed

#69

Post by georgieporgie »

yaix wrote: post #16
machinagod wrote: post #12

There's a couple of regulations for selling GPS enabled devices in China (I am a software guy on a major PND manufacturer with products being sold in China). - The map data is scrambled (GPS coordinates are encrypted). - To correlate a GPS position with the map data, you plug the HW position through an encryption library (which you have to compile in a specific government building in Beijing). - Border drawing is str…

Everywhere in China you can buy illlegally imported smartphones (cheaper, avoids chinese sales taxes) from Hongkong, all with GPS included.

This makes me wonder if I brought my US Android phone to China to use it as a Wifi tablet device, am I technically breaking the law?

Re: All Maps in China are Transformed

#70

Post by tomjen3 »

azov wrote: post #64
jackfoxy wrote: post #63

Historically maps have been closely guarded military secrets. As late as the Renaissance possession of the wrong map could get you executed by European powers, even in peacetime. Rudyard Kipling's novel Kim is largely based on the true story of British surveying and map making in India and central Asia.

AFAIK, military maps are still secret in most places. This is because they contain information that cannot be easily derived from hi-res satellite imagery. Stuff like "how much weight can this bridge support", "how deep is this ford", etc. This is important if you are trying to, say, drive tanks through unfamiliar terrain.

But the thing is that most bridges which has a weight limit on them has that limit on a sign next to them.

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.

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