The covariance matrices represent ellipses.
So the example application on Wikipedia can be visualized like this:
I've been working on the code for a while,
The code is now on github
and I've uploaded the image to wikipedia.
That's a really excellent visualization, and I see what you are trying to do with the skewed grid lines. If you already pretty much know what you're looking for, the lines really let you see how after a change in time,
The thing that is confusing about the grid lines, though, is that in the update frame, the numbers on the position axis still represent the position that the state would have been in at a time
Also, it's possible that the confusion is made worse by the inclusion of negative velocities on the plot. The result of doing this is that the axes numbers are moving in the negative position direction, while almost all of the region corresponding to the states we are interested in is moving in the positive position direction. (Although I guess there is some value in including zero velocity states, since those are the fixed points. And if you stopped at 0, then it would be harder to add the distinction in times I was looking talking about before.)
Finally, and related to the first point, it would probably be nice to have some labels on both of the axes. That's just the middle-school math teacher coming out in me.
Again, really nice work. I'm so glad somebody made this!
answered 01 Mar '12, 09:45