Cassini and Mars: How to Measure the Slope of Rivers

On Cassini we used synthetic aperture radar, did a lot of flybys and it used its synthetic aperture radar to see through the atmosphere because in the visible, Titan's like this featureless orange blob. The problem with the radar is that it's very noisy and it's very low resolution. So I think we've imaged about 20% of the surface at less than 350 meters resolution. And then over two of them, we were able to get slope because there's extremely limited topography data on Titan. That's one of the big data sets that we're kind of missing. Over those two we got the slope of the rivers. Because the rivers are quite wide, right? There