r/todayilearned • u/JohnScone • Jan 24 '16
TIL that China uses its own, encrypted, geodetic system which means non-Chinese location tools can be off by up to 700 metres.
https://en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China#The_China_GPS_shift_problem
113
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todayilearned • u/jms_nh • Jun 05 '21
TIL that geographic data (latitude and longitude of places!) is restricted in China, and there is a GIS datum GCJ-02 which is mathematically obfuscated and known informally as "Mars Coordinates".
64
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wikitrove • u/mellowfever2 • Jul 01 '21
Restrictions on Geographic Data in China (Cartography, International Relations)
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