Live data from Hacker News

Every map of China is wrong

medium.com

51–60 of 275 posts

Re: Every map of China is wrong

#51
> This ultimately means that data reported in GSJ-02 needs to be moderated in some way to account for inaccuracy, and individuals pursuing work in China will be penalised. I don’t have a solution for this,

I'm fairly certain that the NSA does.

Re: Every map of China is wrong

#52
post #50

I remember a couple of years ago someone was claiming the Three Gorges Dam was buckling and about to fail, based on the satellite views showing the top of the dam weaving back and forth. Everyone sane thought it was some interpolation bug from Google trying and failing to tile the pictures properly, but maybe this is the reason why.

It's because when you orthorectify an aerial image, you cast rays from the earth's surface to the camera, so if your model of the earth's surface is off (like when there's a giant man made structure) your mapping also gets wonky.

Re: Every map of China is wrong

#53
post #31
post #27

Earlier quoted context omitted.

At some point it was illegal in NYC to go out with a with a mask on, while it was also made illegal to go out without a mask on. (That was when they were both protests that made them ban masks (that obscure the face), and Covid that made them mandate masks. But I think the laws were written broadly enough that both covering and not covering your face were technically forbidden.)

Do you have any reference for that? I live in NYC and was here for the whole pandemic, and this is the first I hear something like that.

I got it from Matt Levine's Money Stuff, Bloomberg email newsletter. It's the post from 2020/04/21:

> Everything is mask crime

> We talked last week about a hypothetical minimalist legal system with only two crimes: Wire fraud, for stuff you do in your house, and coronavirus-related curfew violations, for stuff you do outside your house. If you go to someone’s house and murder them, that’s violation of your local stay-at-home order and you can be arrested for that; who needs a law against murder? I wrote:

> > You’d need a regime of sentencing enhancements (leaving the house to do murder is worse than leaving the house to jaywalk), and you’d probably need like one more law for domestic violence, but the point is that you can get a pretty parsimonious legal system if that’s what you want. I do not actually think it’s what you want.

> The reason you shouldn’t want it is that any sort of minimalist legal system like this leaves huge room for discretion. If the only crime is a fairly common and trivial one like leaving the house, then the people who get prosecuted and severely punished for it might be the ones who leave the house to do murders, but they might not be. They might be people who leave the house and are otherwise disfavored by the police, prosecutors, judges and juries. Poor people, members of minorities, people with unpopular political beliefs, that sort of thing.

> Anyway a fun fact about New York state law (via public defender Sam Feldman) is that now:

> * It is illegal to be around people without a mask, and

> * It is illegal to be around people with a mask on.

> There’s an executive order requiring masks in public when you cannot social distance, and a state law forbidding them. So pretty much anyone who goes outside in New York is breaking the law. Presumably they won’t all be prosecuted.

He quotes https://twitter.com/srfeld/status/1251228271645208577 as the source.

Re: Every map of China is wrong

#54
post #13

Earlier quoted context omitted.

It seems that even taking geotagged photos is illegal in China, indeed some camera models automatically disable geotagging when inside China: https://ogleearth.com/2012/05/why-do-panasonic-leica-fujifil...

Thanks for the details. It is always interesting how the most innocent things are seen as danger by an autocracy.

For many years, the most accurate (paper) maps of the Soviet Union were those created by the CIA. The USSR's own maps included lots of intentionally incorrect data.

Re: Every map of China is wrong

#55
post #6

So Openstreetmap must be illegal in China! And indeed it is: https://wiki.openstreetmap.org/wiki/China Of course that doesn't stop people from mapping every bench in China https://www.openstreetmap.org/search?query=China#map=3/33.99...

The workaround might be to attach the GPS device to your dog's collar, as was done in Cuba by OpenStreetMappers

Re: Every map of China is wrong

#56
post #50

I remember a couple of years ago someone was claiming the Three Gorges Dam was buckling and about to fail, based on the satellite views showing the top of the dam weaving back and forth. Everyone sane thought it was some interpolation bug from Google trying and failing to tile the pictures properly, but maybe this is the reason why.

It probably doesn't help that reliable sources tell me that the Three Gorges Dam is, in fact, absolutely goddamn crooked and janky. One reason they don't allow close photography of it is simply that it looks so very bad.

Grand Coulee Dam, on the other hand, despite being decades older? It's dead-on level.

Re: Every map of China is wrong

#57

Earlier quoted context omitted.

Indeed, despite its apparent illegality, China seems to be fairly well-supported and well-mapped by OpenStreetMap, at least in major cities. And is entirely mapped in normal WGS-84 without the obfuscation problem. In any case, according to Wikipedia, open-source code is available to convert between WGS-84 and the obfuscated GJC-02 coordinates. Since technology seems to have caught up with it, is there any advantage (…

I want to know why Google hasn’t corrected their map overlays. The shift in the roads makes it frustrating to look at.

Because Chinese law forbids to convert their coordinates to WGS84, and using the Chinese coordinates for satellite data would give a discontinuity at the border. This is explained in the article.

Re: Every map of China is wrong

#58
post #16

Youtuber Johnny Harris released a great video covering China's changing maps: https://www.youtube.com/watch?v=WpQQOQ__1ok&ab_channel=Johnn... It's a detailed analysis of China's 2023 map, which many countries believe oversteps China's boundaries.

That's about border claims, which is a completely separate issue to what the article is talking about.

Re: Every map of China is wrong

#59
post #57

Earlier quoted context omitted.

I want to know why Google hasn’t corrected their map overlays. The shift in the roads makes it frustrating to look at.

Because Chinese law forbids to convert their coordinates to WGS84, and using the Chinese coordinates for satellite data would give a discontinuity at the border. This is explained in the article.

If Google didn't mind breaking the law they could use the previously mentioned, public code to convert the coordinates to the standard format. Could be that it wouldn't be worth it to implement that though.

Re: Every map of China is wrong

#60
I am not a fan of China, but not wanting coordinates of strategic targets in your country to be precisely known doesn't seem crazy. Other restrictions they have like not being able to access the Internet, or being put in reeducation camps, or not having a say in how your government is run would affect me badly. But if navigation in my car worked fine, would I care if topography is a bit distorted? During the pandemic, I saw US federal, state and local government restrict my freedom in much more drastic ways, even after I was already vaccinated. I know it was even worse in China, but I would still focus on these other things and rather than not having precise coordinates of a military base.
Post reply on HN