topographic map non-linear confidentiality algorithm (11. 719)

Lured by the slightly hyperbolic title Every Map of China is Wrong—with one’s mind going elsewhere to Tibet, Taiwan and maritime trade routes at first, via ibīdem, we are directed to a rather fascinating look at geodesic reference points (see also), international standards and those conventions that are the exception. China’s coordinate system is informed by Global Positioning System and the US National Geospatial Intelligence Agency surveys but has inserted an obfuscating formula when it comes to matching satellite telemetry with digital maps and is proprietary (in the name of economic and national security, restricted to a handful of domestic companies which foreign interests must partner with) and cannot be aligned because of the randomness of the algorithm. The drift is especially apparent at border regions and for those travelling between Macau, Hong Kong and the mainland, as those special administrative regions are on the international standard. Much more at the links above.