Post #1916226

2026-04-29 16:48 UTC

Here&#39;s a screenshot of Google maps showing a small portion of downtown Shanghai. You can clearly see that the digital overlay of roads does not line up with the image of the actual roads. I think China dithers the GPS signal as a defensive maneuver to protect sensitive targets. Does anyone know more about this?

Replies (4)

@mralancooper@hachyderm.io 2026-04-29 21:11

So, my suspicion was correct. China dithers geographic mapping information for security purposes. Thanks to @mgiraldo.mstdn.social for the link to the explanation: https://medium.com/@anastasia.bizyayeva/every-map-of-china-is-wrong-bc2bce145db2 (edited to add full name link)

Open ##2141620
@EnidKapelsen@social.cologne 2026-04-29 17:16

@mralancooper Interesting! It might also be the case that redevelopment is faster than Google Maps satellite view updates? I had the opportunity to visit Shanghai during university time and local students explained that they used an updated map to navigate in parts of the city that they did not visit daily. It was pre-google-maps and it was not a joke: We could witness during our short visit how whole areas got bulldozed over night.

Open ##2141621
@mgiraldo@mstdn.social 2026-04-29 17:28

@mralancooper https://medium.com/@anastasia.bizyayeva/every-map-of-china-is-wrong-bc2bce145db2

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@samueljohnson@mstdn.social 2026-04-29 22:32

@mralancooper I've been to a town in Nebraska that wasn't on any road map (in the early 80s) -- paper maps back then.

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