A Cassini press release describes the identification of lakes on the surface of Titan, the large moon of Saturn’s visited by the Huygens probe a couple years back.

The image above shows a false-color representation of radar data, with low backscatter color-coded black-to-blue. I recently blogged about so-so use of false color, but I think the above image does a pretty good job. N.B., however, what the choice of color stretch is doing here. The transition from the warmish colors to the cool blue and black guides one’s eye to “read” the transition as being from solid land to liquid lakes. But we’re trusting the visualizer of the data to have performed that stretch correctly (or I should say, honestly).

This is an excellent example of how images—even those based on data—incorporate subjective elements. The eye perceives the color difference as stark and distinct, but the actual difference in pixel values might be quite small, so the color choice communicates a lot of information in this case. I’m not saying the image is lying or anything; I’m just saying that the image does not give anything near an objective sense of the data.

(There is no such thing as an objective image!)

The results are also reported in the current issue of Nature.