So… “Data Logger Visualization Technology.” That’s a long and uninformative name. Technology that visualizes… data. Data that was at some point logged. What they’re trying to say is that they loaded up a real race car with monitoring gadgets and took note of a bunch of data — steering, throttle, G-force, and all that stuff — and logged it into a file. This file can be read by Gran Turismo 5 and produce essentially a 1:1 recreation of an actual real-world lap. Sure, you could race your own ghost, but why would you, when you can race Michael Schumacher’s?
This is only possible because the tracks and cars are simulated with such meticulous detail in GT5. Various scanning and storage technologies have allowed an almost unbelievable amount of precision, and although it’ll never be the same as actually going 140 around whatever circuit, it’s getting miiighty close.