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I've found that the maps match the GPS of my phone exactly, but the satellite pictures are shifted. Does that mean: 1) My GPS module also gives out obfuscated

I've found that the maps match the GPS of my phone exactly, but the satellite pictures are shifted. Does that mean: 1) My GPS module also gives out obfuscated coordinates when in China or 2) Google uses shifted satellite images?

thaumasiotes 5y ago
> I've found that the maps match the GPS of my phone exactly I can use OpenStreetMap fine in China. But that's not Chinese data. If a Chinese person sends me a location marker on WeChat, the marker will show up (for me, in WeChat) at some other, unintended, location; I can't use that feature at all.
squeaky-clean 5y ago
I wish I had saved some of the links I had found, one source I read said that the non-satellite map data was actually correct, and it was the stitching of the satellite imagery that was incorrect. I had no way to test this and no other source mentioned this, so I ignored it. But it's funny you mention this, #2 might be the case. robotastronaut also corrected me that it's not actually the GPS that is being obfuscated, but the map coordinate system. So your GPS device is probably receiving correct results, but on an improperly projected map.
- SECProto 5y ago
  > one source I read said that the non-satellite map data was actually correct, and it was the stitching of the satellite imagery that was incorrect The opposite is true: If you look at areas like the Macau-Zhuhai border or Hong Kong-Shenzhen, you'll see that the satellite imagery is continuous but the mapping data has discontinuities at the border (some zhuhai streets are halfway across the water to Macau!)
gruez 5y ago
Neither. The satellite images are accurate, and so is your GPS readout. What's shifted is the official data that the government provides (eg. location of roads). more here: https://news.ycombinator.com/item?id=10964450 https://news.ycombinator.com/item?id=10964450

thaumasiotes 5y ago

> I've found that the maps match the GPS of my phone exactly I can use OpenStreetMap fine in China. But that's not Chinese data. If a Chinese person sends me a location marker on WeChat, the marker will show up (for me, in WeChat) at some other, unintended, location; I can't use that feature at all.

squeaky-clean 5y ago

I wish I had saved some of the links I had found, one source I read said that the non-satellite map data was actually correct, and it was the stitching of the satellite imagery that was incorrect. I had no way to test this and no other source mentioned this, so I ignored it. But it's funny you mention this, #2 might be the case. robotastronaut also corrected me that it's not actually the GPS that is being obfuscated, but the map coordinate system. So your GPS device is probably receiving correct results, but on an improperly projected map.

SECProto 5y ago
> one source I read said that the non-satellite map data was actually correct, and it was the stitching of the satellite imagery that was incorrect The opposite is true: If you look at areas like the Macau-Zhuhai border or Hong Kong-Shenzhen, you'll see that the satellite imagery is continuous but the mapping data has discontinuities at the border (some zhuhai streets are halfway across the water to Macau!)

gruez 5y ago

Neither. The satellite images are accurate, and so is your GPS readout. What's shifted is the official data that the government provides (eg. location of roads). more here: https://news.ycombinator.com/item?id=10964450 https://news.ycombinator.com/item?id=10964450