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All Maps in China are Transformed

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Re: All Maps in China are Transformed

#71

Post by joelhaasnoot »

fs111 wrote: post #4

How is this news? I work in the digital mapping world and there everybody knows this. You cannot even get the data out of China, all data has to stay within China and if you want to do map business in China, you can only do it through a joint-venture with a Chinese company. [edit] BTW: India is similar, they are not scrambling the map, but it cannot leave the country either. So as a map-maker you have to have a local…

Getting detailed maps in lots of coutries is difficult. Lived in Ethiopia for a while, which up until 1993 was governed by a communist regime. Around 2000 it was still law that in order to get maps on a 1:10000 scale you needed a government license/permit and could only be bought at the "Mapping Authority". 1:100000 maps on the other hand were available everywhere. Lots of other countries have restrictions for instance on key bridges and other infrastructure, disallowing access, pictures, stopping, etc.

Re: All Maps in China are Transformed

#72

Post by Sniffnoy »

alexqgb wrote: post #62
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

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 ou…

Let's not get mixed up about what the projection did and didn't do. As you point out, the importance of rhumb lines comes not from the fact that the thing they keep constant -- the bearing (with respect to north/south) -- was something that could actually be measured.

Rhumb lines are not, however, the shortest distance between two points on a sphere. Those would be great circles. In particular, note that along a rhumb line one can never reach the north or south pole. Indeed, rhumb lines are dependent on your choice of poles, which the actual shortest course clearly cannot be!

Re: All Maps in China are Transformed

#73

Post by orijing »

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…

> "There's China" I said. "And there's Taiwan."

You knew her disposition. (You were her friend). What was the goal of that comment, to incent a fruitless political discussion?

Edit: Whoa there. Why the downvotes? I am genuinely curious why the parent decided it was a good idea to stoke that discussion. I have friends whose political views are far from mine, and there are just DMZ topics that I don't dare bring up. For example, a discussion about the Federal Reserve and Operation Twist would be fruitless with my Libertarian friends, who just have a different opinion on that, which I believe is irreconcilable. I would say that's the same situation with Taiwan-strait politics.

Re: All Maps in China are Transformed

#74

Post by Game_Ender »

georgieporgie wrote: post #67
marshray wrote: post #51

Earlier quoted context omitted.

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. :-)

They might have some local GPS jammers to make it harder for unmanned drones or bombs to navigate near the building.

Re: All Maps in China are Transformed

#75

Post by ctl51 »

First - that post is 3 years old.

Secondly - I lived in Beijing for half a year in 2010 (ie. 2 years after this post was published). I used Google Maps often on my smartphone, and the GPS fix on the features map was incorrect (ie. I would be standing at a street corner and it would show me a few hundred meters down the street on the map).

Re: All Maps in China are Transformed

#76

Post by barrkel »

orijing wrote: post #73
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…

> "There's China" I said. "And there's Taiwan." You knew her disposition. (You were her friend). What was the goal of that comment, to incent a fruitless political discussion? Edit: Whoa there. Why the downvotes? I am genuinely curious why the parent decided it was a good idea to stoke that discussion. I have friends whose political views are far from mine, and there are just DMZ topics that I don't dare bring up. Fo…

Facts as concrete as physical dimensions are not really open to political debate.

Re: All Maps in China are Transformed

#77

Post by ugh »

DizzyDoo wrote: post #40

This reminds me of the Peters Projection, one of the weirder attempts to map the oblate spheroid nature of the earth to a 2D plane. http://www.petersmap.com/

Many people will know about this projection (and first have heard about different projections in general) from The West Wing episode Somebody’s Going to Emergency, Somebody’s Going to Jail (http://en.wikipedia.org/wiki/Somebody%27s_Going_to_Emergency...).

Re: All Maps in China are Transformed

#79

Post by Sniffnoy »

Sniffnoy wrote: post #72
alexqgb wrote: post #62

Earlier quoted context omitted.

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 ou…

Let's not get mixed up about what the projection did and didn't do. As you point out, the importance of rhumb lines comes not from the fact that the thing they keep constant -- the bearing (with respect to north/south) -- was something that could actually be measured. Rhumb lines are not, however, the shortest distance between two points on a sphere. Those would be great circles. In particular, note that along a rhum…

Argh. Misnegation from earlier version. "As you point out, the importance of rhumb lines comes from the fact that..." -- there shouldnt' be a not there.
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