The map generated by reports about the presence or absence of oil using Oil Reporter, an open data application built by CrisisCommons and its allies.

A nonprofit initiative's open-data, citizen-journalism project offers a clear picture of the progress of oil across the Gulf of Mexico wherever everyday people can get close enough to the water to report what they see.

Oil Reporter, a project of the loosely organized nonprofit Crisis Commons, offers a pretty complete picture of where oil is, and even where it isn't, based on the reports that people have been submitting via smartphone applications. The reports contain the latitude and longitude of the reporter, ratings between one and ten on how much oil is there, whether oil has affected wetlands, and whether there is oil-affected wildlife present. People who use the app can also include a picture.

Citizens have reported oil sightings and sent pictures of oil, both the tarballs and sludge that washes up and the slicks that loom out at sea.

There are conflicting reports, including one that reports “all clear off shore 1-4 miles off shore From Pensacola pass to Destin,” but that one is refuted by several other people.

It's the crowd in action: Messy, not always clear, but pretty accurate, all things considered. It's important to note that these are snapshots of the location of a moving target — the oil slick, the tarballs, and the sludge are all presumably on the move at all times.

It does seem more useful to look at the map than to follow the official Deepwater Horizon news feed. A recent press release sent by the joint federal-BP response team encouraged people to disbelieve “rumors” that oil had arrived in Pensacola, for example.

From the press release:

“Yes, there are tar balls here and there,” said Bianca Ephraim, a receptionist at the National Parks Service, “But our water is clear as glass.”

But citizen journalists, and official reports accessible from the Deepwater Horizon website if you know where to look, had already reported a more complete truth: While Pensacola is safe for now, it's protected by Pensacola Beach, which is actually stretch of beaches on a sandy bar. Those beaches have been closed for days now due to oil.