Wired – no paywall: “Marine insurers and oil traders want to know what’s going on in one of the world’s most critical waterways. As the volume of disappearing ships in the area increases, analysts are getting creative…Tracking disappearing ships makes use of several technologies, some of them newer than others. Samir Madani, the cofounder of TankerTrackers.com, has for years relied on satellite imagery from both commercial and public sources to give paying clients a better sense of when and where oil and other goods are moving in and out of the strait. But in April, US satellite firms announced they would limit high-resolution imagery of the region. “We are dusting off all the old sources and tweaking them to perfection,” Madani told WIRED in a message. “We are buying [information] from other Western sources as well.” The firm’s data is valuable to other companies, he says, because two-thirds of tanker traffic moving through the Strait of Hormuz is by vessels with histories of violating sanctions. Bockmann says her firm relies on several other sources to get a good idea of what’s going on in the strait. Electro-optical imagery uses electronic sensors to detect visible and near-infrared light data. Synthetic-aperture radar uses microwaves to create images even through clouds, rain, or darkness. Radio-frequency signals are used to transit data wirelessly (used in Wi-Fi, Bluetooth, and GPS). Stitch those together with databases that include ship registry information and even “human presence signals” from mobile devices onboard vessels, and the firm can get a better sense of what is going where. Generally, satellite imagery used to be very expensive to obtain, but prices are coming down, she says…”