Blanked-Out Spots on Baidu Maps
Our breakthrough came when we noticed that there was some sort of issue with satellite imagery tiles loading in the vicinity of one of the known camps while using the Chinese mapping platform Baidu Maps. The satellite imagery was old, but otherwise fine when zoomed out — but at a certain point, plain light gray tiles would appear over the camp location. They disappeared as you zoomed in further, while the satellite imagery was replaced by the standard gray reference tiles, which showed features such as building outlines and roads.
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Having established that we could probably find internment camps in this way, we examined Baidu’s satellite tiles for the whole of Xinjiang, including the blank masking tiles, which formed a separate layer on the map. We analyzed the masked locations by comparing them to up-to-date imagery from Google Earth, the European Space Agency’s Sentinel Hub, and Planet Labs.
