Just prior to the Chinese New Year holiday, Baidu published a heat map that showed the most popular travel routes within China. It got some attention for showing which parts of the country were most impacted by the insane chunyun travel rush.

Now it’s being put to use for another purpose: showing what’s happened in Dongguan following the crackdown on prostitution in the city. As you can see below, the rush is on, and it’s in one direction: away from Dongguan.

Asia Sentinel reports a full 10% of the city’s population is involved in the sex trade, or some 800,000 people. And once police began busting brothels, it was time to get the hell outta Dodge:

That prompted an exodus from the city in all directions – although, according to Baidu’s heat map, a full quarter of the departures headed for Hong Kong in a hurry. According to the Tech in Asia website, Baidu gathers data from smartphones with Baidu Maps and other apps using its location-based platform to create the heat map. Baidu Maps alone has more than 200 million registered users and receives 3.5 million position requests every day, according to Tech in Asia. The heat map updates every four to eight hours, showing the most popular destinations, points of origin, and travel routes.

According to the map, in a report made public in the Hong Kong-based Marketing.trade publication, other cities that were destinations for the fleeing tourists were Ganzhou, Jiangxi, Guangxi Yulin, Chenzhou, Hunan and Zhejiang Ningbo. The Baidu live map visualizes the hottest migration routes. From 12 noon to 8 pm, the rush was on.

The question now is whether the sex trade will return to Dongguan, à la regularly shuttered pirated DVD shops, or the party is well and truly over.